Examples of orthogonal polynomials in several bariables --
General properties of orthogonal polynomialsin several variables --
Root systems and coxeter groups --
Sperical harmonics associated with reflection groups --
Classical and generalized classical orthogonal polynomials --
Summability of orthogonal expansions --
Orthogonal polynomials associated with symmetric groups --
Orthogonal polynomials associated with octahedral groups and applications.

This is the first modern book on orthogonal polynomials of several variables, which are interesting both as objects of study and as tools used in multivariate analysis, including approximations and numerical integration. The book, which is intended both as an introduction to the subject and as a reference, presents the theory in elegant form and with modern concepts and notation. It introduces the general theory