Aspects of W_\INFTY Symmetry

Abstract

We review the structure of W_\infty algebras, their super and topological extensions, and their contractions down to (super) w_\infty. Emphasis is put on the field theoretic realisations of these algebras. We also review the structure of w_\infty and W_\infty gravities and comment on various applications of W_\infty symmetry.

(24 pages)