Paulo Ribenboim treats numbers as personal friends in this collection of expository essays. Topics include prime numbers, Fibonacci numbers (and the Arctic Ocean!), the classical work of Gauss on binary quadratic form, Euler's famous prime producing polynomials, powers, irrational and transcendental numbers. The essays are written in a light language without secrets and are thoroughly accessible to everyone with an interest in numbers. Other books by the author are "The New Book of Prime Number Records", "The Little Book of Big Primes", which have enjoyed a considerable success, and the recent "Fermat's Last Theorem for Amateurs" (1999).