I read e: The Story of a Number by Eli Maor. This book was a very fast read. The book was laid out in a very easy to read format, with each chapter talking about the history of some aspect of math. At the end of each chapter there was a short section on some of the derivations that were talked about in the chapter. The back of the book had additional appendices to show more derivations and show how some other parts of the book were concluded.
I liked the layout of the book. Just talking about the history of a discovery and some of the most essential math in the actual chapters of the book was a good move by the author. This helped focus the chapter on the essentials of the history. It also allowed for those that have less mathematical background in general or on a specific subject to be able to finish a chapter and understand what the key messages were. Adding the additional parts at the ends of chapters and the appendices were also good, because those that have more background in the subject or want to know more could go and look at those sections and find the derivations. Personally, there were some that I looked at, and others that I found less interest in and just skipped over because I was not interested in the topic.
As far as the content goes, I found the book to be VERY interesting. I chose this book by the recommendation of Duncan Vos and because I knew that being a science major as well, learning more about the number e would be more helpful than many other things that I could have chosen to read. The history behind the number e is very long. It has many twists and turns that finally get to the ending value of 2.7182818284. The naming of the number also took many years, it was initially called just the inverse of the logarithmic function, but Leonard Euler (of course) was the one that gave it the letter e.
The book was a definite good read, but I would not suggest it to everyone. The material is very interesting to those that like to learn the history/origins of numbers and ideas, but if that is not your favorite thing to read about, I would shy away from this book. A major flaw of the book comes in that aspect, in that, the author talks about feuds between families and the discovery of calculus, but doesn't do a great job tying all of the aspects of the book together well. He gets all the major discoveries that lead up to the number, but again, unless you have background knowledge in the area of e or enjoy having a history lesson, the book is not for you.