From the creator of the wildly popular webcomic xkcd, a hilarious and informative book of popular science that provides answers to important questions you probably never thought to ask.

Millions of people visit xkcd.com each week to read Randall Munroe’s iconic webcomic. His stick-figure drawings about science, technology, language, and love have a large and passionate following.

Fans of xkcd ask Munroe a lot of strange questions. What if you tried to hit a baseball pitched at 90 percent the speed of light? How fast can you hit a speed bump while driving and live? If there was a robot apocalypse, how long would humanity last?

In pursuit of answers for these fascinating thought experiments, Munroe runs computer simulations, pores over stacks of declassified military research memos, solves differential equations, and consults with nuclear reactor operators. His responses are masterpieces of clarity and hilarity, complemented by signature xkcd comics. They often predict the complete annihilation of humankind, or at least a really big explosion.

The book features new and never-before-answered questions, along with updated and expanded versions of the most popular answers from the xkcd website. What If? will be required reading for xkcd fans and anyone who loves STEM books and pondering the hypothetical.

Randall Munroe’s fully-researched, deeply unserious answers explore:

• Absurd Science: From draining the oceans to building a periodic table out of the actual elements, discover the often-explosive consequences of taking silly ideas seriously.
• Hypothetical Questions: What would happen if you tried to hit a baseball pitched at 90% the speed of light? Or if a robot apocalypse finally happened?
• Physics Explained: Munroe breaks down complex topics like relativistic physics and thermodynamics with clarity, wit, and detailed computer simulations.
• Signature Stick-Figure Comics: Each answer is complemented by the iconic xkcd comics that make complex science accessible and hilarious.