The Practice of Kalachakra by Glen H. Mullin (Snow Lion 1991)
The Wheel of Time, the Kalachakra in context. Geshe Lhundub Sopa et al. (Snow Lion, 1985)

The way to Shambala by Eric Bernbaum (out of print and hard to get)
Masters of Mahamudra by Keith Dowman, Suny 1985. (See nrs. 22, 24, 27, 46, 52, 54, 77)

Taking the Kalachakra Initiation, Alexander Berzin (Snow Lion 1997) ISBN 1-55939-084-0

Encyclopedia of Tibetan Symbols by Robert Beer (Serindia)

Advanced Books on Kalachakra:

The Kalachakra Tantra, Rite of Initiation. Tenzin Gyatso the Dalai Lama and Jeffrey Hopkins (Wisdom, 1985)
Kalachakra Initiation, Madison 1981
Kalacakra Tantra by Geshe Ngawang Dhargyey (Library of Tibetan Works and Archives, 1983)
Kalacakra Sadhana and Social Responsibility, David Reigle, Spirit of the Sun Publications 1996.

Transcending Time An Explanation of the Kalachakra Six-Session Guru Yoga, Gen Lamrimpa and B. Allan Wallace (Wisdom 1999) ISBN 0-86171-152-1

For more general books on Buddhism, visit my other website: Buddhism 2001.