What If? takes on all sorts of questions, from the potentially possible (Could you make a jet pack by firing guns at the ground? How hard would a hockey puck have to be hit to knock a goalie back to the net?) to extremely hypothetical. (What would happen if a pitcher threw a baseball at 90% of the speed of light? If every human disappeared, how long would it be before the last light went out?) There are also a few "Weird (and Worrying) Questions from the What If? Inbox" through the book, that get very brief answers. ("Is it possible to cry so much you dehydrate yourself?" -- Karl Wildermuth. "...Karl, is everything OK?") And there are plenty of stick figure cartoons interspersed throughout the book, to comment on the answers/
Even though I couldn't follow most of the math and much of the science here, I enjoyed What If? a lot. Munroe mixes scientific explanation with humor seamlessly, There are lots of funny footnotes ("If it's past the year 2016 right now when you're reading this, hello from the distant past! I hope things are better in the future. P.S. Please figure out a way to come get us.") and "citation needed" uses for pretty accepted facts. Some answers are quite surprising (such as what would happen if everyone on Earth was in the same place and jumped at once; nothing would happen to the Earth, but there's be mass death and the collapse of civilization as all the humans tried to escape from that one area) and it's hard to disagree with Munroe's answers. Even if What If? is beyond your science understanding, it's still funny and informative.
Overall grade: A-
Reviewed by James Lynch