Characters of Groups and Lattices over Orders From Ordinary to Integral Representation Theory

This is the first textbook leading coherently from classical character theory to the theory of lattices over orders and integral representations of finite groups. After the introduction to simple modules allowing a non degenerate invariant bilinear form in any characteristic the author illustrates step by step the approach given by Sin and Willems. Dirichlet characters and results on primes in arithmetic progressions are given as applications.