Book excerpt: Solving Geometric Constraints records and explains the formal basis for graphical analysis techniques that have been used for decades in engineering disciplines. It describes a novel computer implementation of a 3D graphical analysis method - degrees of freedom analysis - for solving geometric constraint problems of the type encountered in the kinematic analysis of mechanical linkages, providing the best computational bounds yet achieved for this class of problems. The technique allows for the design of algorithms that provide signification speed increases and will foster the development of interactive software tools for the simulation, optimization, and design of complex mechanical devices as well as provide leverage in other geometric domains.