This book is a little out of date and a little too basic. It is for the beginner and is not an advanced text. The best thing that it is short. Because it is so short, it had to be packed densely with information, no wordiness. I've never had enough time to read The Codebreakers book, too big. Here I got informed in minimal time and the book is much less expensive -- it's got a better cost to read ratio and cost to information ratio.