From the creator ofthe wildly popular webcomic xkcd comes this hilarious and informative book of answersto important questions you probably never thought to ask.Millions of people visit xkcd.com each week to read RandallMunroe's iconic webcomic. His stick-figure drawings about science, technology,language, and love have a large and passionate following. Fans of xkcd askMunroe a lot of strange questions. What if you tried to hit a baseball pitchedat 90 percent of the speed of light? How fast can you hit a speed bump whiledriving and live? If there were a robot apocalypse, how long would humanitylast?In pursuit of answers, Munroe runs computer simulations,pores over stacks of declassified military research memos, solves differentialequations, and consults with nuclear reactor operators. His responses aremasterpieces of clarity and hilarity, complemented by signature xkcd comics.They often predict the complete annihilation of humankind, or at least a reallybig explosion.The book features new and never-before-answered questions,along with updated and expanded versions of the most popular answers from thexkcd website. What If? will berequired reading for xkcd fans and anyone who loves to ponder the hypothetical.