5 out of 5 Stars!

FBI Agent Gardner Camden is one of the quirky agents in the Patterns and Recognition (PAR) unit, a unit that has a very specific purpose. To solve cases that nobody else can solve. When DNA from a murder victim comes up as a match for a serial killer that was presumed dead, PAR gets into action. This serial killer was supposed to be dead. How did he end up murdered years later? While they are investigating the murder, another body is being discovered. As they try to figure out what is going on, they start to uncover clues that point back to them. The PAR unit will have to work fast to uncover the riddles that the killer has left them. Can they uncover this killer while keeping themselves safe?

WOW! First 5/5-star book of 2025! “Head Cases” by John McMahon was the book I was hoping would set the stage for 2025, and it fulfilled that for me. If you are a fan of criminal TV shows, like Criminal Minds, you will absolutely love this book as much as I did. I felt like I was watching a TV show play out in front of me, with clues and detective work that left you wanting more.

Compared to other mysteries and thrillers, I thought this book was very different but in a great way. For starters, this was a very fast-paced book. More than what I am used to with a real investigation unfolding with a major time element. There was never a dull moment in this novel. While Agent Gardner Camden is trying to figure out who this killer is in his head, they are uncovering new clues and figuring out their next moves. This book had major action throughout, and I promise you, you will not get bored. I thought “Head Cases” was refreshing and felt so real. Yes, I understand they may not solve cases like this as fast as they did and what not, but the flow of the novel felt realistic.

Agent Gardner Camden was a smart character with an interesting backstory. I loved hearing the thought process inside his head and all of his emotions throughout this book. I don’t want to say anything to spoil the book, but his story with his daughter was really sweet and a touch of what his novel needed. I really liked all the characters in this novel and their backstories as well. Everyone in PAR has a story about why they ended up with the unit, and you will discover all of their secrets throughout the story, which adds another element of surprise.

Like I said before, if you are a crime fan or love Criminal Minds, you will LOVE “Head Cases” by John McMahon coming out January 28th, 2025. While reading the acknowledgments, I saw this book is 1 of a 2 part book deal. So, if you read this book and are wanting more, keep an eye out for a sequel coming out!

Thank you to St. Martin’s Press, John McMahon, and Netgalley for a digital ARC of this novel in exchange for my honest review.

Head Cases follows FBI Agent Gardner Camden who is part of PAR unit in the FBI and he was chosen by the director to lead a new case where an old suspect of Gardner's that was supposed to have died a few years ago in a fire has now shown up dead. With the second victim the team sees that a pattern is being established, that the killer they are hunting is hunting serial killers.

Gardner reminded me of Agent Reid from Criminal Minds, who I love so this made the book very appealing to me. For fans of criminal minds this book will definitely be a great read for them. The rest of the team was also very interesting and I hope we see the different relationships blossom next book specially Gardner's and Cassie's. I also hope in the next book we find out more about Shooter as her character was very interesting to me.

PAR usually focus on cold cases so this case was a different take for the team, I hope on the next books we do see the team investigating and solving a cold case.

This was my first book from John McMahon but definitely will not be my last, as this book is the first in hopefully a series about the PAR Unit I cannot wait to see where the next books takes the team.

I gave this book 4.5 stars but rounded for 5 stars as there are no half stars here and the book was closer to 5 stars then to 4.

Thank you to NetGalley and St Martin's Press for this ARC in exchange for an honest review.

"Head Cases" by John McMahon seems like a good thriller for fans of "Criminal Minds."

Unfortunately for me, I was unable to get into the story itself. I made it to 33% but it just wasn't for me. I found myself not caring about the characters or the storyline enough to continue.

Thank you to NetGalley and Minotaur Books for selecting me for this ARC.

**Head Cases** is a gripping psychological thriller featuring FBI Agent Gardner Camden, a brilliant but emotionally distant investigator in the Patterns and Recognition (PAR) unit, which tackles complex cases others have abandoned. Camden’s analytical genius contrasts sharply with his struggles to connect with those around him, including his young daughter, adding depth to his character as he navigates a chilling murder investigation.

The plot centers around a serial killer linked to a brutal murder through DNA evidence, increasing the body count and leading Camden into a psychological game with the killer. The killer’s cryptic clues create a tense cat-and-mouse dynamic that keeps readers engaged.

McMahon skillfully develops the PAR unit as more than just competent agents; their quirky interactions provide comedic and poignant moments that balance the story’s darker themes. Camden's personal journey, particularly his troubled relationship with his daughter, adds emotional weight to the narrative, highlighting the costs of his professional life.

As the investigation unfolds in real time, moving from cold case analysis to active pursuit, tension mounts, amplifying the stakes. **Head Cases** is not only a meticulously crafted whodunit but also a character-driven exploration of human connections and the psychological toll of duty. With sharp writing and unexpected twists, John McMahon offers a thrilling read that will leave crime thriller fans eagerly awaiting his next work.

I enjoyed this book. It gave me Criminal Minds vibes... a team of FBI Agents are put together to solve crimes. I liked the pacing of the story and how the characters got along, as well. I was thinking the serial killer would go one way, and the main character thought so also, and he didn't actually go that way, he twisted it up and went sideways! The book kept my guessing and held my interest.

Amazingly fast read and so interesting that I didn’t want it to end. I sat down and couldn’t put the book down loved the cases and can’t wait for more.

This book was very entertaining. It is about a unit inside the FBI called Patterns and Recognition (PAR). Gardner Camden is part of that unit. He is, I thought, on the spectrum but a genius at puzzle solving. So that being said he can crack some cases that the FBI have problems with. The story is about a serial killer killing other serial killers. One of those killed serial killers was thought to be dead seven years ago. But because of DNA they do realize that he was alive and hiding out until he was killed by the "serial killer". The serial killer seems to always be one step ahead of PAR which is another puzzle in itself. There are some twists and turns in this book but not anything that wasn't believable. It was a great read with some really awesome characters who were very well developed throughout the story. If you are a John Sandford or Michael Connelly fan you will definitely enjoy this read.
Thanks to #netgalley, #minotaurbooks and @johnmcmahonbooks for an ARC of this great read. All opinions are my own.

📚 #BOOKREVIEW 📚
Head Cases (PAR Unit, Book 1) by John McMahon
⭐️⭐️⭐️⭐️ / Pages: 352 / Genre: Police Procedural
Release Date: January 28, 2025

FBI Agent Gardner Camden is an analytical genius when it comes to solving crimes and puzzles but a complete noob when it comes to interacting with people. He’s part of the Patterns and Recognition (PAR) unit, which also includes a mathematician, a weapons expert, and a computer analyst. In this first book of the series, DNA of a dead serial killer turns up at a murder scene, which then leads to more clues specifically made for Gardner. Can he figure out who’s responsible before it’s too late?

I enjoyed this thriller and the characters in it. I know I’d hate dealing with someone like Gardner in real life, but for some reason I really like reading about them. I’ll be keeping an eye out for this series.

Thank you, @JohnMcMahonBooks, @StMartinsPress, and @NetGalley for my gifted copy.

PAR or Patterns and Recognition is a special unit within the FBI. It consists of four agents and one supervisor. The agents all have special talents and blemished personnel files. Normally they never leave their office in Jacksonville, but when an old case is reopened they’re sent out into the field. A serial killer’s body who they thought had died in a home fire years ago suddenly turns up in Texas.
A thrilling whodunit with a likable protagonist and riveting plot. Gardner Camden, who is tasked to lead the investigation, is socially inept but a total whiz when it comes to figuring out patterns and solving puzzles. I like how he’s aware of his shortcomings and works to overcome them. He shows a lot of personal growth as the story progresses. He’s got a great team around him and they have each other’s backs. The plot has some twists and turns to ratchet up the suspense level as well. It’s a good story. 4.25 stars

Let's hear it for the dad fiction (what my husband calls this)! It's the start of a new series of what seems to be a police procedural, but FBI.

FBI Agent Gardener Camden is neuroatypical. He works in a division of misfits to solve the puzzles of investigations. A serial killer has re-emerged and they are on the case. I did enjoy this book and look forward to following the series. I would have liked more on all of the character, but maybe that is coming later in the series.

Thank you to NetGalley and Minotaur Books/St. Martin's Press for an advance copy for my honest review.

Remember the golden era of Criminal Minds? Head Cases gave me such nostalgic vibes reminding me of the best parts of the show. So naturally I couldn’t put it down! Simply inhaled it within 24 hours! And yes, definitely a binge worthy story.

An FBI team consisting of exceptional “oddballs” on a hunt for a Dexter style serial killer? Sign me up immediately. Am I already obsessed with Gardner Camden, the neurospicy main character? You know it! As someone whose brain does not function in the same way as what’s considered “neurotypical”, I love reading about “neuroatypical” characters. I especially loved other characters described through Gardner’s eyes and details he focused on.

The red herrings along the way were great. As were the twists! But more than anything it was the characters that made me so invested in the story. I’m so glad I read the author’s at the end and found out book 2 is already in the works. I’m definitely committed to this series and hoping there’ll be many many more books in it!

A huge thank you to Minotaur Books for my ARC and to John McMahon for writing it!

Great start to a new series. I appreciate so much having a neurospicy MC whose story is not all about his neurodivergence - it's just one facet of who he is. The characters were developed well, and the relationship between the MC and his partner is great. I love her character as well and their interactions feel genuine. I think McMahon did a great job of not giving away the story too soon and saving a few twists for the end. I will say - this is not for the faint of heart or stomach! I will definitely look forward to the next book in the series and plan to go back and read his other books as well.

4.5 stars

"Head Cases" by John McMahon is a new, yet different kind of, police procedural that keeps you on the edge of your seat from start to finish. The plot had many twists and turns [literally and figuratively], making it both exhausting (poor Gardner just couldn't stop traveling) and a real page-turner. McMahon’s characters are well-developed and relatable, adding depth to the story. While some parts may feel a bit predictable, the overall experience is highly enjoyable and satisfying.

A great read for fans of murder and police dramas - I'm very excited to see what comes next for the PAR.

Thank you to St. Marten's Press for my copy of HEAD CASES. This one is out Jan 28.

I really wanted to like this one but it was just so sterile and not at all interesting. I didn't really care about any of the characters and it was hard to stay connected to this story. I don't recommend this one.

Agent Camden is part of a small group of FBI agents in the PAR department. They handle cases that no one else can solve and have exceptional qualities at solving riddles and seeing patterns that other agents can’t. The team is dispatched to Texas, where a serial killer has been murdered. While investigating that crime another serial killer is murdered. What ensues is a cat and mouse game between Camden and the killer. This is your usual run of the mill police procedural concept. What I was hoping for was a bit more grit to it. I felt the characters were too one dimensional and I didn’t feel any attachments to them. They were just “ characters in a story.” The crime itself definitely had interesting aspects to it but again didn’t get into that dark, gritty type of book I enjoy, however I do believe anyone who enjoys a police procedural without getting too graphic this would certainly like this one.

Thanks to NetGalley and the publisher for my ARC in exchange for an honest review.

The ultra braniac, best problem solvers but a little socially inept FBI agents are in one department that everyone else jokingly calls "Head Cases". Each one has unique talents but also had an issue that landed them in the PAR department. When DNA leads to a serial killer declared dead long ago and other criminals are being murdered, the PAR unit is tasked with finding out who is seeking vigilante justice, how/if they are related and why. If you love puzzles, you will love this book and how they put the pieces together. Can't wait for the next book about these amazingly talented FBI agents!

Thank you to St. Martin's Press and NetGalley for the ARC!

John McMahon’s Head Cases is a brilliant start to what I hope will be a long-running series featuring the FBI’s Patterns and Recognition (PAR) unit. With its razor-sharp puzzles, dynamic team dynamics, and heart-pounding suspense, this book is impossible to put down. I devoured it in record time and am already eagerly awaiting the next installment—though I’m almost sad I read this one so early, knowing the wait for the sequel may be long.

At the center of the story is Gardner Camden, a genius investigator with a remarkable talent for solving puzzles, but a frustrating inability to connect with people, including his young daughter, Camila. As part of the quirky and highly specialized PAR team, Gardner dives into an investigation that’s as chilling as it is intricate. DNA evidence linking a murder victim to a long-presumed-dead serial killer sets off a series of twists, turning the hunt for the killer into a deadly game of cat and mouse.

McMahon excels at creating complex characters, and the PAR team is no exception. Each member, from the mathematician to the computer analyst to their no-nonsense leader, adds depth and personality to the story, making the team feel like a family of misfits with unparalleled talent. The riddles and patterns the team deciphers are not only intellectually satisfying but also integral to the emotional stakes of the plot.

The audiobook, courtesy of Macmillan Audio, takes the experience to another level. The narrator perfectly captures the nuances of Gardner’s analytical mind, the banter between the team members, and the tension of their race against time. Each character is distinct, making it easy to follow the ensemble cast, and the narration brings the book’s puzzles and high-stakes action to life.

I’m deeply grateful to St. Martin’s Press for granting me access to the book via NetGalley and to Macmillan Audio for the audiobook. Both formats are phenomenal and equally engaging, and I highly recommend them to fans of intricate, character-driven mysteries.

Head Cases is a triumph of intellect, suspense, and heart. McMahon has crafted a series debut that feels fresh and engaging, with a case that is as clever as it is thrilling. If you’re a fan of ensemble casts, intricate puzzles, and high-stakes thrillers, don’t miss this one. And like me, be prepared to count down the days until the next book in the series!

This gripping debut features FBI agent Gardner Camden, an expert at puzzle-solving, and his colleagues in the Patterns and Recognition (“PAR”) Unit, a sort of A-Team of misfit agents each exceptional at some particular skill—computers, olympic-caliber precision shooting, math, etc. This premise feels like one of those TV shows in which a motley team of crime-fighters uses its diverse skills to catch the bad guys, but there’s a reason those shows are fun. Who doesn't love a socially inept, crime-solving genius with a solid group of talented teammates? Here the group is on the trail of a killer targeting serial killers. Fortunately, the relentless drama and action are focused on the chase from the point of view of the good guys (sort of like a thriller meets procedural), without the currently fashionable but gruesome tendency to focus on the criminals or their point of view. For the agents in PAR, there’s not much sleep and a lot of flying around the country trying to beat the bad guy to the punch. Meanwhile, the team members all have their own quirks as well as career mistakes that caused them to get assigned to this squad, which may or may not be targeted by the higher-ups for the chopping block. All of this makes for a compelling story that I hope is the beginning of a series.

Thanks to Netgalley and St. Martin’s Press/Minotaur Boks for a digital advance review copy.

⭐️⭐️⭐️
I had mixed feelings about this book. Most of it was slow, and I struggled to stay engaged for the first two-thirds. However, the pace picked up at the end, going fast and furious, which I enjoyed. The ending was good, though not surprising.

I’ve heard people compare this book to Criminal Minds, but I didn’t get that vibe. Maybe I’m an outlier, but it lacked the emotional depth and team dynamics I expected.

Gardner Camden is an interesting lead—analytical and focused—but felt a bit one-dimensional. The PAR team had potential, but I wish they were explored more. The riddles and puzzles were a nice touch, but not as impactful as I’d hoped.

It wasn’t bad, but it didn’t grab me until the end. Fans of procedural thrillers with lots of logic might enjoy it more than I did.

Thank you, NetGalley, Macmillan Audio, and St. Martin’s Press, for the e-ARC and audiobook in exchange for my honest review!

This was such a strong start to a new series, if you’re a fan of Criminal Minds or other shows like that this was excellent! This follows an FBI team of misfits called PAR as they race to solve a complex and tricky case. I really liked that the team wasn’t a bunch of super agents with stellar records, instead they’re made of up individuals who toe the line and have some behavioral issues and quirky tendencies. The concept of a serial killer hunting other serial killers was fantastic and lent to a fast paced and exciting ride. The characters were well developed, the case was complex and twisty and the entire thing was gripping, definitely recommended!