An Introduction to Sieve Methods and Their Applications - Paperbackby Alina Carmen Cojocaru (Author), M. Ram Murty (Author) Sieve theory has a rich and romantic history. The ancient question of whether there exist infinitely many twin primes (primes p such that p+2 is also prime), and Goldbach's conjecture that every even number can be written as the sum of two prime numbers, have been two of the problems that have inspired the development of the theory. This book provides a motivating introduction to sieve theory.