1. A Review of Commutative Harmonic Analysis.- 2. Ergodic Theory and Kronecker's Theorems.- 3. Diophantine Approximation.- 4. General Properties of Dirichlet Series.- 5. Probabilistic Methods for Dirichlet Series.- 6. Hardy Spaces of Dirichlet Series.- 7. Voronin Type theorems.- 8. Composition Operators on the Space H2 of Dirichlet Series.