Type synthesis is the process of determining possible mechanism structures to perform a given task or combination of tasks without regard to the dimensions of the components. The "structure" or "topology" of a mechanism is defined by the number of links, the number of joints and their type (revolute, prismatic, etc.), the connectivity of the links and joints, and which links are to be considered ground and input(s). A systematic procedure for type synthesis, suitable for computer implementation, is introduced. The large body of literature pertaining to type synthesis is discussed in the context of the proposed procedure.