The aim of this study is twofold: to investigate the content and function of a group of cult mediations known as the Four Forms of Samadhi that were central to the early T'ien-t'ai tradition of Chinese Buddhism; and, on the basis of these findings, to look into various aspects of Buddhist devotional and liturgical usage during the late North-South Dynasties, Sui, and Early T'ang period. The first section includes a detailed discussion of the institutional organization of early T'ien-t'ai religious practice and the place of the Four Forms of Samadhi within this context. The content and structure of the meditations are described in full, and a framework is established--both theoretical as well as institutional and practical--that allows us to see specific forms of religious discipline within a more comprehensive context of spiritual development. In chapter two the historical origins of the Four Forms of Samadhi are traced, and their significance is assessed with respect to broader patterns of cult devotionalism evidenced among Buddhists of the North-South Dynasties, Sui, and early T'ang. In the third chapter, the rites of the Four Forms of Samadhi are compared with those found in various Buddhist liturgical/devotional manuals of roughly the same period. Continuities in the internal liturgical structures as well as the context of application of different rites are examined, typologies drawn up, and key points of form and process discussed. The conclusion proposes that the T'ien-t'ai Four Forms of Samadhi participated in (and, thus, reflect) a broadly based tradition of Chinese Buddhist devotional/liturgical practice that began to take definite shape during the sixth century. This tradition is itself shown to be deeply rooted in Indian/Central Asian liturgical and devotional legacies, yet, a development that, in its particular form, is unique to East Asia. Annotated translations of T'ien-t'ai Chih-i's two most complete samadhi manuals are appended: the influential Fa-hua san-mei ch'an-i/hsing-fa ('Procedure for Performing the Lotus Samadhi Repentance') and the Fang- teng san-mei hsing-fa ('Procedure for Performing the Fang-teng Repentance').