The subject of this study is a small collection of songs known as Caryagiti, 'songs of the mystic path', or literally 'songs of the proper way of action'. Although the songs were composed perhaps sometime in the 9th-12th century CE, and thus belong to the final phase of Indian Buddhism, their authors, known as siddhas, have defied attempts of historians to place them within an exact historical context, just as they, in their own time, openly defied all religious and social conventions. Many of the songs depict the daily life of the people among whom the siddhas lived. The present volume provides a systematic analysis of this imagery, but it also attempts to uncover the profound doctrine based on Buddhist concepts of spiritual liberation and yogic techniques, which, at least according to the Sanskrit commentary, is the esoteric message of the songs. These songs hold a unique place in India's spiritual and literary heritage, yet in many ways they have been imperfectly understood. This study clarifies many points that have hitherto remained obscure and provides a fresh and deeper insight into their structure and contents.