Before you go on a cosmic road trip, feed the residents of New York City to a T. rex, or jump on a geyser as it erupts, be sure to consult this practical guide for impractical ideas. Bestselling author and xkcd creator Randall Munroe consults the latest research on everything from swing-set physics to airplane-catapult design to clearly and concisely answer his readers’ outrageous questions. As he consistently demonstrates, you can learn a lot from examining how the world might work in very specific extreme circumstances. Filled with bonkers science, boundless curiosity, and Randall’s signature stick-figure comics. Hardcover, 368 pages. (Available separately: What If? Volume One, item WE8292.)