The full title is "What If?: Serious Scientific Answers to Absurd Hypothetical Questions", which pretty much sums up the book. The book was a present from my friend Terry, who is a fan of the author's online comic xkcd.com which mixes scientific fun with stick figure art. Users can submit "what if" questions at the site and this book is a collection of responses. For example, "What if a rainstorm dropped all of its water in a single giant drop?". He then discusses the details of the physics involved in the impact. But the descriptions are full of snarky wording like, "Unfortunately for the old-timers on the porch...". Or humor hidden in the illustrations of a magnitude -2 earthquake. (Yes, that's a real thing). Most of the scenarios involve some ridiculous initial condition, but then accurately follow what *would* happen. Lots of stuff you wouldn't consider at first glance. You need to understand a little physics, but its a silly fun book.