In this book, Randall Munroe answers a series of hypothetical questions that are rather absurd - many relating to various sciences and applying different equations and concepts. The questions were ones that people asked/posted on a website he created so theoretically he is answering real questions people are curious about.
This book is most definitely for very curious people. Munroe is very creative, and often humorous as he goes through hundreds of random questions and answers them scientifically to the best of his ability. I often found the questions extremely hypothetical and thus, rather boring. I think the enjoyment of this book is very dependent on the person, I would almost think it is best for middle school boys.
But he does do an excellent job, and it must have been fun to write - and honestly, reading it makes me want to meet the author because he seems like a very humorous but also intelligent person. Randall Munroe seems like the kind of person you might meet in a coffee shop and be absolutely astounded at his ability to both explain things in an understandable and brilliant way, as well as do it while making you laugh.