Table of Contents

1 Fermat.- 2 Euler.- 3 From Euler to Kummer.- 4 Kummer’s theory of ideal factors.- 5 Fermat’s Last Theorem for regular primes.- 6 Determination of the class number.- 7 Divisor theory for quadratic integers.- 8 Gauss’s theory of binary quadratic forms.- 9 Dirichlet’s class number formula.- Appendix: The natural numbers.- Answers to exercises.