This book presents a unified theory of the Finite Element Method and the Boundary Element Method for a numerical solution of second order elliptic boundary value problems. It is one of the first books on Theory of Boundary Element Methods.
From the reviews:
“Steinbach introduces known fundamental solutions ... for the potential equation, linear elasticity, the Stokes system, and the Helmholtz equation. ... For a reader who has a basic knowledge of functional analysis, Steinbach’s book is a nice and relatively compact introduction to the error analysis of Galerkin boundary element methods and its fast realization.” (Hans-Görg Roos, SIAM Review, Vol. 52 (4), 2010)