This is an extended second edition of The Topology of Torus Actions on Symplectic Manifolds published as PM 93 in 1991. The material and references have been updated. Symplectic manifolds and torus actions are investigated, with numerous examples of torus actions, for instance on some moduli spaces. Although the book is still centered on convexity results, it contains more theorems, more (and better) proofs, more exercises, and many figures. This enlarged version, although it includes all the material treated in the first edition, is indeed a new book.