Singularity theory draws on many other areas of mathematics and, in turn, contributes to many areas both within and outside mathematics, including differential and algebraic geometry, knot theory, differential equations, bifurcation theory, Hamiltonian mechanics, optics, robotics and computer vision. This volume consists of two dozen articles from some of the best known figures in singularity theory, and it presents an up-to-date survey of research in this area.