Substantial advances in the realm of isoquinoline alkaloids have occurred since The Isoquinoline Alkaloids, Chemistry and Pharmacology, was published in 1972. The present volume represents an effort to describe important developments since that time. The organization of the present book is essentially the same as in The Isoquinoline Alkaloids. Each chapter begins with a discussion of structural elucidation and synthesis, a description of typical reactions then follows, and the chapter ends with coverage of biogenesis, pharmacology, and spectroscopy. New chapters have had to be added to describe the completely new alkaloidal types discovered since 1972. These include baluchistanamine (an isoquinolone- benzylisoquinoline dimer), the aporphine-pavine dimers, the 4,5-dioxoapor- phines, the secoberbines, the 3-arylisoquinolines, eupolauridine, and very recently imerubrine. Another new chapter discusses the chemistry of the aristolo- chic acids and aristolactams, a group of substituted phenanthrenes, obviously of isoquinoline derivation in spite of the fact that they do not incorporate a basic nitrogen function. The aristolochic acids and aristolactams were not in- cluded in The Isoquinoline Alkaloids even though they were known at the time that book was written. On the other hand, one group of alkaloids which was included in The Isoquinoline Alkaloids and nevertheless was deemed not to belong properly in the present work is the naphthalenoisoquinolines, which include ancistro- cladine and its relatives. These bases do not originate biogenetically* from tyrosine, and beside incorporating tetrahydroisoquinoline moieties show no clear structural relationship to the more orthodox isoquinoline alkaloids.