This is part one of a two-volume work presenting a comprehensive treatment of the finite-dimensional variational inequality and complementarity problem. It covers the basic theory of finite dimensional variational inequalities and complementarity problems. Coverage includes abundant exercises as well as an extensive bibliography. The book will be an enduring reference on the subject and provide the foundation for its sustained growth.

Solution Analysis I.- Solution Analysis II.- The Euclidean Projector and Piecewise Functions.- Sensitivity and Stability.- Theory of Error Bounds.