Four profound books for developing one's understanding of the Bodhisattvayana and Tantrayana path.  Keep them all for your library or offer  the ones you already own to your local Dharma center.

The Kalachakra Tantra: Rite of Initiation

By His Holiness the Dalai Lama, translated by Jeffrey Hopkins (Wisdom Publications)

Associated with the promotion of world peace, the Kalachakra — or "Wheel of Time" — tantra is one of the most detailed and encompassing systems of theory and practice within Tibetan Buddhism. Kalachakra Tantra contains a complete translation of the Kalachakra initiation ritual as conferred by His Holiness the Dalai Lama in Toronto in April 2004, along with his commentary, and a comprehensive introduction by Professor Jeffrey Hopkins that explores the Kalachakra's rich symbolism, meaning, and history. The book also includes the Six-Session Yoga.

Diety Yoga: In Action and Performance Tantra

By Lama Tsongkapa, His Holiness the Dalai Lama, edited by Jeffrey Hopkins (Snow Lion Publications)

Deity Yoga describes the profound process of meditation in Action and Performance Tantras. It is an invaluable book for anyone who is practicing or is interested in Buddhist Tantra. The book is comprised of three parts:

Heart of Mantra by the Dalai Lama is a lucid exposition of the meditative rites of deity yoga--the distinctly tantric process in which yogis visualize themselves in the form of a Buddha's divine body as a manifestation of compassionate wisdom.

The Great Exposition of Secret Mantra--parts 2 and 3 by Tsong-ka-pa, details the practices of Action and Performance Tantras. Special deity yoga techniques for the development of the heart, mind and physical form of a Buddha are presented in a coherent series of yogic exercises. The mudras (hand gestures) that accompany the meditations are clearly illustrated.

Supplement by Jeffrey Hopkins outlines in detail the structure of Action Tantra practices as well as the need for the development of special yogic powers.

The Wheel of Time: The Kalachakra in Context

by Geshe Lhundrup Sopa, Roger Jackson, John Newman, forward by HH the Dalai Lama, edited by Beth Simon (Snow Lion Publications).

The Kalachakra, or "Wheel of Time," is one of the most profound and sublime of the Buddhist tantric systems. It is an intricate interweaving of astrology, eschatology, physiology, and yoga into a meditational path system that embraces the entire material universe and leads to complete, perfect enlightenment.

The Kalachakra, with its special connection to the land of Shambhala and a future golden age of Dharma, has a special appeal for people of all levels of learning and practice. Initiation into its practices traditionally have been large public events, especially when granted by the Dalai Lama.

Initiation into the Kalachakra Tantra has been given with increasing frequency in recent years, but information on this complex system and practice remains sparse. The Wheel of Time attempts, in part to fill the gap.

The book opens with a Foreword by His Holiness the Fourteenth Dalai Lama. Then, the five articles discuss, respectively, the Buddhist background, history, initiation rites, generation stage sadhana, and completion stage practices of the Kalachakra Tantra. Each article is accessible to the non-specialist reader interested in Buddhism, to the aspiring practitioner, and to the scholar as well.

The Guide to the Bodhisattva's Way of Life

by Vesna A. Wallace & B. Alan Wallace (Snow Lion Publications)

In the whole of the Tibetan Buddhist tradition there is no single treatise more deeply revered or widely practiced than A Guide to the Bodhisattva Way of Life. Composed in the eighth century by the Indian Bodhisattva Santideva, it became an instant classic in the curricula of the Buddhist monastic universities of India, and its renown has grown ever since. Santideva presents methods to harmonize one's life with the Bodhisattva ideal and inspires the reader to cultivate the perfections of the Bodhisattva--generosity, ethics, patience, zeal, meditative concentration and wisdom.