The subject of this book is libretto: the history of the genre, the profession of the librettist, and the ways of creative collaboration in musical theater between the composer, the dramaturg and the producer. The paucity of research on this subject is striking. In its 415-year history, musical theater had not witnessed a single attempt to produce a “learning manual” of the kind offered here. In that sense, this book truly is unique. The purpose of the book is to serve as a guide for conservatory students studying to be composers, dramatists, conductors, producers, vocalists, and music or theater scholars. It offers material for reflection for their instructors as well. Because of its robust content, clear and engaging style, and complete rejection of textbook didacticism or sterile dogma, the book will also be attractive to a wider audience of musical theater aficionados.