One should be familiar with single-variable calculus to read this book. This book is heavy on actual mathematics and should be read with pencil and paper at hand.
There are ten chapters spanning 246 pages. The topics include: coding theory, Pick's Theorem, Fermat's Little Theorem in relation to decimal expansions, space-filling curves, the birthday paradox, normal probability distributions, Stirling's Formula, information theory, the Fibonacci numbers, the Golden Ratio, prime Lucas numbers, Taylor approximation, Pade approximation, continued fractions, and proving numbers are irrational. Each chapter has problems for the reader to work out, solutions, and suggestions for further reading. The chapters are not entirely self-contained and should be read in order. Most results in the text are proven with full mathematical rigor.
The title of this book is misleading. I almost didn't pick it up off the shelf because of pictures of cute bunnies on the cover. This book is deeper than those pictures or the title let on. It goes way beyond recreational mathematics. I think it did a tremendous job filling in some holes in my mathematical education by presenting some results that aren't ordinarily covered in the standard math major curriculum. Every serious student or teacher of mathematics should read this book immediately.
There are a few things that set this book apart. One is that the author is relentlessly honest. He doesn't try to hide anything from the reader. Once near the end of a proof I was thinking that something wasn't right, that we didn't cover all cases. Then suddenly I read "You may have the nagging feeling that there is something a bit fishy going on." I laughed out lous and continued to read as the author filled in the holes. Another thing that sets this book apart is the way the author begins with some exciting ideas, results, or questions, and then lets the mathematics unfold in a natural way in order to answer the questions. Everything is well-motivated ahead of time. No time is wasted building up mathematical machinery only to use select parts of it. I always wished my textbooks were written this way.
I was immediately hooked on this book and couldn't put it down. But if you aren't, keep reading. Somehow the chapters get progressively more interesting and exciting. I must admit that the first chapter wasn't as captivating as the rest. Chapter Two is about Pick's Theorem. I had known this theorem for many years, but only from math contests, not from my coursework. As such, I had never seen a proof before reading this book, and was surprised to find out how simple and elegant such a proof is. I was further surprised to see an application of this theorem to a result about Fibonacci numbers in chapter 8. In fact, the book abounds with interconnections between the chapters.