This formidable publication essentially constitutes an authoritative English translation of Tsong Khapa's monumental and seminal work on the five stages of the perfection phase. Broadly speaking, the fundamental system of practice of the Highest Yoga Tantra (anuttara-yogatantra) consists of two consecutive and integrated phases or stages, namely the generation or creation stage (utpatti-krama), and the completion or perfection stage (saṃpannakrama). In the creation stage the yogi practises meditative visualizations of individual or groups of deities arranged in maṇḍalas. The primary goal of this stage is to purify the yogi's body and mind, and to transmute or transform them into a subtle or deity's body. Then in the perfection stage the yogi advances in five steps towards the completion of the entire practice, which concludes in the attainment of enlightenment.

The short Tibetan title of Tsong Khapa's work, given on the title page, merely indicates that it is an exposition or elucidation of the five stages (pañcakrama). On the other hand the long title of this work clearly indicates that it is an exposition of the five stages of the Guhyasamāja.

There are two major traditions or schools that provide bodies of correlated commentaries and works on the Guhyasamāja: the Noble Tradition and the School of Jñānapada. Tsong Khapa's exposition of the five stages of the completion phase largely follows the Noble Tradition. The name of this tradition is not attested in the available Indian sources, but it is derived from its Tibetan name gsang ‘dus ‘phags lugs (the Noble Tradition of the Guhyasamāja). This tradition includes a group of Indian tantric masters and their successors, who produced a collection of commentaries and works on the Guhyasamāja and related literature, but it also makes references to other tantric texts. The principal masters of this tradition are Ārya Nāgārjuna and Āryadeva, and their successors Nāgabodhi and Candrakīrti. As these masters of the Noble Tradition have the same names as Nāgārjuna and other masters of the Madhyamaka school, the Tibetan tradition maintains that they are the same, despite the fact that their lives are separated by several centuries. The primary scriptural authority of this tradition is the Guhyasamāja and its explanatory tantras. The works of Nāgārjuna constitute the principal explanatory authority, in particular his Pañcakrama is treated as the seminal work that delineates the five stages of the completion phase. Nāgārjuna's successors agree that there are five stages, but they disagree on the identity and sequence of these stages. Tsong Khapa discusses the sequence of these stages and explains them in the following order: body isolation, speech isolation, mind isolation, clear light, and non-dual union. These five stages form an integrated path, which starts with the purification of the body and concludes with the attainment of the non-dual enlightenment.

Structurally, Tsong Khapa divides his work into six parts, and then subdivides each part into major and minor segments. Parts 1 to 5 serve as the basic background, in which he explains the categories of the tantras, the centrality of the Guhyasamāja and related issues and sources. Part 6 forms the main body and provides a detailed exposition of the five stages. In the actual publication, Tsong Khapa's work is helpfully divided into eleven chapters, but Tsong Khapa's divisions of his work are retained and indicated in bold numbers and letters within the body of the translation. In addition to the translation, this publication contains the author's introduction which comments on Tsong Khapa's versified prologue, three glossaries, two bibliographies, and three indexes.

The literary style of Tsong Khapa's work emulates the genre of Indian and Tibetan treatises (śāstra). The entire work is interspersed with numerous quotations and references to an array of Indian and Tibetan masters and sources. The intellectual discourse is tenacious and lofty, and assumes a great deal of knowledge on the part of the reader. It is not the kind of work written for beginners, but rather for scholars well acquainted with the Buddhist tantras, in particular with the Guhyasamāja doctrines and literature. Thus it is the category of work that one pensively studies rather than reads and absorbs at a reasonable pace.

Thurman must be congratulated and praised for his magnificent, competent and lucid translation of Tsong Khapa's monumental and erudite work. His translation definitely constitutes a mighty and admirable contribution to the study of the Guhyasamāja system.