1. Elliptic problems.- 1.1 The Dirichlet problem for the Laplace equation in an annulus.- 1.2 Examples of Dirichlet problems in an annulus.- 1.3 The interior and exterior Dirichlet problems.- 1.4 The Poisson integral for the disc. Complex form. Solution of the Dirichlet problem when the boundary condition is a rational function R(sin ?, cos ?).- 1.5 The interior and exterior Dirichlet problems.- 1.6 Boundary value problems for the Poisson equation...