This dissertation offers the first comprehensive overview of a little-studied Chinese Buddhist ritual compendium known as the Ritual Instructions for Altar Methods (Tanfa yize). Attributed to the mid-Tang translator and Buddhist mage Amoghavajara (704-774), the collection contains some forty-two individual items spanning some four fascicles. Thematically, the work can be divided into two main parts. The first contains thirty-four individually named and numbered ritual texts, appended to which is a lengthy transmission account. In addition to providing a section outline of this voluminous work, the present study provides an account of the extant Duhuang manuscript copies of the text, and considers their paleographical and codicological features in an attempt to aid in its dating and reconstruction. Specifically, this study finds that the received text circulated in the Dunhuang region during the late-medieval period, and the late tenth century more specifically.