This is a study in the archaeology of asceticism within the context of religious studies, and looks at carvings of ascetics on temples at Srisailam, Hampi-Vijayanagara, Sringeri, and other sites in South India, dated mainly to the fifteenth and early sixteenth centuries, the time of the Vijayanagara empire. The book seeks to establish that in this important body of ascetic images there is a distinct and numerous group with their own iconography who are the Siddhas. Siddhas are found in India from mythological times until the present day. From the early centuries CE into the medieval period the Siddhas are advanced ascetics practising tantra, yoga, and alchemy, who are common to Hinduism and Buddhism. They played an important part in the history of Buddhism, taking the Vajrayana to Tibet, China, Java, Sumatra, and Cambodia. There are sections on the temple sites of the Siddhas, their history and that of associated sects. The archaeological technique of line drawings together with photographs is used for iconographical analysis. First is the Siddha as yogin, for hathayoga is pre-eminent and concerned with supernatural powers and immortality. The Siddhas developed and propagated yoga over the centuries and the Siddha tradition continues today in India and with a diffusion around the world in the form of yoga. Then comes the Siddha as alchemist and as a dancer followed by an examination of the enigmatic and highly symbolic set of images with Siddhas seated on an extraordinary variety of vahanas - creatures from fish and tigers to scorpions. The immense range of hair styles is studied and their dress and equipment. Finally, the different strands of Siddha iconography are drawn together to establish the Siddha as an essential part of the the religious art and history of India.