This book is only about numbers - that is, whole numbers and nothing but the whole numbers, which start from from 0, 1, 2, 3, 4...and go on forever. Here you can meet perfect numbers, happy numbers, lucky, untouchable, weird, narcissistic, evil and deficient numbers, not to mention nice Friedmans and multi-legged repunits, as well as primes and their cousins, the sexy primes. It is also full of fascinating facts and curios, prime number conjectures, the sieve of Eratosthenes, the Fibonacci series, and much more besides. This is an accessible, clearly explained approach which will appeal to recreational maths enthusiasts, puzzle solvers, and mathematicians of all ages.