Fans of xkcd ask Munroe a lot of strange questions: What if you tried to hit a baseball pitched at ninety 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? What if everyone only had one soulmate? What would happen if the moon went away?

In pursuit of answers, 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 his signature xkcd comics. (They often predict the complete annihilation of humankind, or at least a really big explosion.)

In celebration of ten years of unusual insight, Randall Munroe has revised his classic blockbuster to ask what if? times ten. The result is ten times the adventure of scientific inquiry. This special anniversary edition is far more than a book for geeks, What If? explains the laws of science in operation in a way that every intelligent listener will enjoy and feel much smarter for having listened to.