This book gave me serious Alex Cross/James Patterson vibes, which I mean as a complete compliment. Telling the story of Gardner Camden, an FBI agent, working for the PAR department (essentially a superteam of people with autism), this moved very quickly and implanted you right into the story from the get-go. I actually wondered if it was a sequel and I was unaware (it's not). I also enjoyed the vigilante serial killer aspect, and was surprised by the twist as well.

I would really enjoy reading more books featuring Gardner, and definitely enjoyed John McMahon's style of writing.

As a huge fan of Dexter, Criminal Minds, and Bones, this book was right up my alley! Following an FBI team as they tracked down a serial killer who was hunting other serial killers? Yeah, I was hooked from the start. I loved being alongside the characters as they pieced together the mystery; it felt like I was part of the team working to crack the case.

One of McMahon’s biggest strengths was his attention to detail in the investigative process. The way the case unfolded felt meticulous and immersive, like I was right there with the agents, connecting the dots. It wasn’t a mystery you could solve on your own, but watching everything come together was so satisfying. Every new discovery added a layer to the story, keeping me completely engaged from start to finish.

That said, I did have a small gripe with the character development. Camden, the main character, had a lot of unique traits that made him stand out, but instead of letting us see those traits naturally through his actions, the book repeatedly told us about them. It didn’t ruin the experience for me, but I do wish his personality had been revealed in a more organic way rather than being constantly reinforced.

Overall, this was a fun read for those of us who love solving crimes and getting fully immersed in the procedural details. It was dark, twisty, and full of intriguing characters, making it a great pick for fans of FBI thrillers with a unique angle.

Thank you to #NetGalley and St. Martin's Press for a chance to read this in exchange for an honest review!

Thank you to NetGalley, John McMahon, and St. Martin's Press for the ebook. This is an excellent police procedural series that will keep you on the edge of your seat. A thrilling and engaging read!

To say I enjoyed FBI Agent Gardner Camden is an understatement. I loved his eccentricities, and he has quite a few of those. But his intelligence and his passion are truly fun to watch…uh…I mean read about! (This needs to be a TV series!) I love a flawed character!

Along with Gardner, the Patterns and Recognition unit of the FBI consists of a mathematician, a weapons expert, a computer analyst, and their leader, a career agent. Each of them must use every skill they have to solve the riddle of the killer’s identity. And what a riddle this story is! I enjoyed the chase across state lines and all the deductions. The author truly created an intricate pursuit of a killer!

The narrator, Will Damron was magnetic. Honestly, I am going to have to be on the look out for more books by this guy!!

Need a good hunt for a killer…THIS IS IT! Grab your copy today.

I received this novel from the publisher for a honest review.

This book pulled me in from the first page! I loved the main character and enjoyed the way he analyzed the case in front of him. You really got to get into his head and were able to see how he thought of things. It was a fast paced read, I just had to know what happened next. I can’t want for the next book to come out!

Head Cases is book one in the brand new series PAR Unit by John McMahon.
This book was so great - it has a fantastic plot, an engaging and well-developed cast of characters and great pacing.
I was immediately intrigued by the storyline and the complexities in the plot. It kept me captivated throughout the novel.
This book is an intriguing, fast-paced thriller with well-rounded characters and an exhilarating plot.

This was an excellent book. I had a great time getting to know the characters and watching their relationships change. They were an intelligent and interesting group. The mystery was also interesting with little intricacies. I loved how the MC put it together and the reader was privy to his thought process. I did not have this one figured out early on and it was nice to watch it all unfold. It took a moment in the beginning to get used to the writing because the MC is very unique so it felt strange to be in his head, but once I settled in it was a fun ride.

This was my first book by McMahon and I'm so glad I jumped on this series with the first book. I can't wait to see where the team goes from here. I'm already looking forward to the next book in the series.

This was an intriguing mystery that had me guessing. There were plenty of twists and turns and puzzle pieces to fit together. The story came together and wrapped up nicely. I am looking forward to the next installment.

Thank you to NetGalley and the publisher for the ARC of Head Cases by John McMahon. This gripping thriller is packed with tension, dark secrets, and an unpredictable mystery that kept me engaged. McMahon’s writing is sharp and immersive, pulling me into the mind of the protagonist as he navigates a case filled with twists and moral dilemmas. The psychological depth adds layers to the story, though some parts felt slightly rushed or underdeveloped. One flaw that stood out was the pacing—while the book starts strong and keeps the tension high, certain key revelations felt hurried, making it difficult to fully absorb the emotional weight of the twists. A bit more time spent unpacking the consequences of these moments could have made them more impactful. Despite this, the story remains compelling, and Head Cases will appeal to fans of dark, thought-provoking crime fiction.

If you like Criminal Minds, Benedict Cumberbatch's Sherlock, this book is for you! Someone is gruesomely killing bad people. Is it a vigilante or are they doing it for some other twisted reason. The PAR team is run by Camden an analytical genius who loves solving puzzles. This is interesting, I love the team and can't wait to see what they'll do next.

I wanted it to be the Criminal Minds, Spencer Reid, BAU book of my dreams - and unfortunately, it was only okay for me. I felt the pacing was wildly off - so quick at time and other times it dragged with description and conjecture. I didn't love the backstory of our main character - it felt a bit far reaching for something that would, assumingly, have some level of a secret clearance.

At the end of the day, this was just an okay police, detective book - but with all the framework needed to be something better.

Calling all fans of CRIMINAL MINDS! This book is for you. The crimes in this book were twisted, the characters interesting and the plot was good. I'd definitely read more of the PAR team.

What a fun start to a new series! While the plot did feel a little rushed, I really enjoyed the characters and I’m interested to see how they develop in future novels.

Thanks to NetGalley & St. Martin's Press | Minotaur Books for the chance to read this book!

I'm so glad the cover of this book was so intriguing, I am ashamed of myself to admit but I did often judge a book by it's cover and there was something about this one, that was an instant click and request for me! I love series about FBI Groups & this one was done beautifully! It was like reading a REALLY GREAT mini-series of criminal minds, which I've always wanted to do! It feels like you get so much more out of reading these type of things, you get so many more little details. I was a little worried about some of the stuff being over my head, the terminology and all the little fancy words CSI people use but it was actually quite easy to understand and anything you don't they explain expertly.

It was honestly just great, the suspense it made you feel and even the moments you don't normally get to see of these agents, all the sweet little snippets of Camden and his daughter. Very fast paced read for me, and I loved every minute of it! I will def be looking out for the next one in the series and the Author's other books also

Head Cases is 1st book in the PAR Unit series by John McMahon. Not sure why but I never really connected with this book. At times I found it to move really slow, and I didn't seem to like any of the characters in the book. Having said that I am sure many will really enjoy this book so for that reason I would recommend it to others.

I received and ARC from NetGalley and St. Martin's Press, and I am leaving my review voluntarily.

I really enjoyed this one. While maybe the storyline isn’t that astounding but the characters make for such an entertaining read! This is set up to be one a great series and I’m hoping for that. Thanks to the publisher and netgalley for this copy for read and review

This crime procedural book easily captured and kept my attention. Focused on a special unit of the FBI in charge of cases no one else can solve, it immediately made me think of Criminal Minds and was a great listen,

As the PAR unit hunts for a killer who is offing serial killers, they trek back and forth across the country, having meetings aboard private jets and sending different members to different locations. It is fast paced, action packed, and adrenaline filled. The characters are unique, with interesting individual skill sets that make them an unstoppable team when put together.

This was a great start to a new series, and I will absolutely be ready to read the next installment.

The audio was narrated by one of my favorites, Will Damron. He does an incredible job navigating all of the characters, the building tension, and the action packed moments.

Thank you to Minotaur for the gifted arc and Macmillan Audio for the audiobook. All opinions are my own,

5 stars! If you liked ‘Mindhunters’ on Netflix, you will love this book. It starts off fast and keeps up that pace. I read/listened to this book in 24 hrs, it was that good!

I’m a sucker for anything that can mirror the thrills I get from watching Criminal Minds on television. Head Cases came very close to that I must say. It was action packed, full of shocking and bizarre criminal behavior, along with a cast of lovable, relatable characters. It was quite busy moving from location to location that I sometimes had to stop and figure out where the drama was unfolding, but overall I think this was a great series starter.

Solid story, good suspense, interesting characters. Excellent misdirects, which are important in a mystery/thriller. Not a new idea as such but well executed and it definitely kept my attention: stayed up way too late on my second reading day and then picked it up again immediately when I woke up too early the next morning. I’ll definitely read the second book in the series when it comes out.

Only quibble: some of the poisoning information is incorrect - but I only know this because I worked in toxicology for 8 years. I doubt it’s going to matter to to most readers.