The infinite space, half-space or bi-material considered in the previous chapter has at most one straight line boundary. More straight line boundaries are encountered for a wedge with two sides or a multi-material wedge with multiple interfaces and two outer sides. Several different boundary conditions of wedges have been considered and solved in Hwu (2010). Since most of the wedge problems are considered asymptotically around the wedge apex not for the entire region, instead of the complete solutions only certain particular solutions or homogeneous solutions (or called eigenfunctions) are obtained analytically. Sections 5.1 and 5.2 provide particular solutions for the wedges subjected to forces on the edges and apex, and Sect. 5.3 provides the orders of stress singularity as well as eigenfunctions for multi-material wedge spaces and multi-material wedges with four different boundary conditions. The near tip solutions, the unified definition of stress intensity factors, and the path-independent H-integral for interface corners are discussed and coded in Sect. 5.4. Common functions and examples are then presented in the last two sections.