Written by established authorities in the field, the comprehensive reviews combine descriptive chemistry and mechanistic insight and yield an understanding of how the chemistry drives the properties. Volume 94 of "Advances in Heterocyclic Chemistry" commences with a review of cascade reactions on heterocyclic synthesis. The chapter presents a fascinating array of complex sequences which provide efficient routes to a wide variety of heterocyclic systems. The second chapter is the twelfth in the series on the organic chemistry of heterocyclic ligands in metallic complexes. The present contribution deals with the chemistry of polypyridine ligands in organomanganese and organorhenium complexes. Its current importance can be measured by the fact that, of the nearly 700 references, approximately half date from the last 10 years. Preparation of aminoisoxazoles and their utility in the synthesis of condensed systems are also covered. In the final chapter, isothiazolium salts and their use in synthesis are reviewed. Many condensed S,N-heterocyclic systems are described in this, the first review dedicated to this topic. It contains up-to-date results in the subject which continues to gain importance and expand. It makes available to graduate students and research workers in academic and industrial laboratories the latest reviews on wide variety of heterocyclic topics. The series forms a very substantial database covering wide areas of heterocyclic chemistry.