Covering vertical-rising aircraft as envisioned from the earliest concepts to the period when the helicopter became practical machine in the 1930s, this text focuses on the many pioneering ideas and efforts that led to the creation of today's modern helicopter, whilst exploring possibilities for the future. Inside are over 200 illustrations and an encyclopedic glossary that seeks to enable the reader to understand the development of the technology and procedures. It is intended for professionals, students, and aviation enthusiasts and conservators.