1. Introduction.- 2. Preliminaries.- 3. Preliminaries on Harmonic Functions.- 4. Green Identities and Layer Potentials.- 5. Preliminaries on the Fredholm Alternative Principle .- 6. Boundary Value Problems and Boundary Integral Operators.- 7. Poisson Equation and Volume Potentials.- 8. A Dirichlet Problem in a Domain with a Small Hole.- 9. Other Problems with Linear Boundary Conditions in a Domain with a Small Hole.- 10. A Dirichlet Problem in a Domain with Two Small Holes.- 11. Nonlinear Boundary Value Problems in Domains with a Small Hole.- 12. Boundary Value Problems in Periodic Domains, A Potential Theoretic Approach.- 13. Singular Perturbation Problems in Periodic Domains.- Appendix.- References.- Index.