This chapter discusses the calculation of Casimir energies and provides results for virtually any possible situation that can arise concerning spherically symmetric boundaries. It deals with arbitrary dimension and scalars, spinors, and the electromagnetic field. The chapter determines the dependence of the Casimir energy on the parameters of the theory as, e.g., the mass of particles. It derives the calculation of Casimir energies for scalar fields with Dirichlet boundary conditions and Neumann boundary conditions.