Excursions in Number Theory

This book is a fun romp through number theory. Don't be fooled by the short chapters, the book packs a few punches. But it's still an accessible intro to number theory. While the data related to finding primes by computer is hopelessly out of date, the rest of the material is still very relevant. It was a lucky find in a second hand book store, and together with Lara Alcock's book, it rekindled my interest in maths.