The music of the primes.

I'd like to recommend a book, its called "the music of the primes, why an unsolved problem in mathematics matters" by Marcus Du Sautoy. It is without a doubt one of the best books I have ever read.
As you can tell from the title the book is about the importance of prime numbers, how they play an important role in things like internet security and encryption, quantum mechanics and computer science. Specifically it is about the quest to solve the most famous unsolved problem in maths, the Riemann hypothesis.
The level of maths given is perfect to give you an idea of what's going on and to keep enthusiasts like me happy but not too complicated so that you feel overwhelmed by it. More importantly the human story behind the maths is gripping and will keep you reading on even if you are not very maths savvy. The tales of the incredible people who played a role in the quest is just as interesting as the mathematics they produced.
I can never get bored of reading this book and would recommend it to anyone.