In this chapter we will use the Method of Moments to solve surface integral equation problems involving three-dimensional objects of arbitrary shape. This will allow us to treat many problems of practical interest such as those found in electromagnetic interference (EMI), electronics packaging, scattering, radar cross section, and antenna design. This area has received significant attention in the literature in the last thirty years, and many different methods of treating 3D surfaces of general shape have been considered.We will consider one of the most commonly used approaches, where the surfaces are described using flat, planar triangles, and the currents expanded using the well-known Rao-WiltonGlisson (RWG) basis functions. In Chapter 7, we treated several dielectric and dielectric/conducting junctions of limited type. In this chapter, we will use the method outlined in  to treat junctions with a much more general configuration.