Abstract: We study generalized Robin boundary conditions and Robin-to-Dirichlet maps for Schroedinger operators on bounded Lipschitz domains $\Omega \subset \bbR^n$, $n\ge 2$. In addition, we will derive Krein-type resolvent formulas connecting Schroedinger operators with generalized Robin boundary conditions to those with Dirichlet boundary conditions. This is based on joint work with Marius Mitrea.