Murder by Death

I absolutely loved this.  Imagine mixing a very intelligent adult's ability to communicate with the enthusiasm, curiosity and wild imagination of a 12-year-old, and that is exactly what you get in this book.  With cartoons.  I had no idea stick figures could be so freaking hilarious.

What If? is a collection of questions - out there questions - people have submitted to xkcd.com, hoping for rational, science-backed answers.  These are high hopes because quite a few of the questions aren't actually rational (or scientific, really).  The author does his best to really, accurately answer using physics, math, and some chemistry - and then often has some fun with it, too ("what if we add more power?").  The stick-figure cartoons add illustration and hilarity, and the occasional footnotes cracked me up.  Some of the best parts, though, were the "weird and worrying questions" sections: the ones that couldn't - or shouldn't - be answered but were submitted anyway.

If you're looking for serious science about serious subjects stay very far away from this book, it's not going to meet that need.  But if you enjoy science and occasionally find that you're asking yourself questions like: "what if everyone in the world jumped up at the same time, in the same place?" and actually want to know what would really happen?, this is a book you'll enjoy, if not laugh out loud at.