Randall Munroe is here to provide the best answers yet to the important questions you probably never thought to ask. The millions of people around the world who read and loved ‘What If?’ still have questions, and those questions are getting stranger. Planning to ride a fire pole from the moon back to Earth? The hardest part is sticking the landing. Hoping to cool the atmosphere by opening everyone’s freezer doors at the same time? Maybe it’s time for a brief introduction to thermodynamics. Want to know what would happen if you rode a helicopter blade, built a billion-storey building, made a lava lamp out of lava, or jumped on a geyser as it erupted? Okay, if you insist. Welcome (back) to the mind-blowing world of ‘What If?’ Unfazed by absurdity, Randall consults the latest research on everything from swing-set physics to airplane-catapult design to clearly and concisely answer his readers’ questions.