The Kalachakra Tantra - Rite of Initiation For the Stage of Generation – by the XIV Dalai Lama and Jeffrey Hopkins
A commentary on the text of Kay-drup-ge-lek-bel-sang-bo , and the text itself.
A Commentary on the Kalachakra Tantra
— by Geshe Ngawang Dhargyey
Contains explanations and advice concerning the various commitments and initial practices.
Ornament of Stainless Light - An Exposition of the Kalacakra Tantra — by Khedrup Norsang Gyatso (Library of Tibetan Classic - volume 14)
The Kalacakra texts present an amazingly detailed theory of cosmology and astronomy, especially about the movements of the various celestial bodies.
Introduction to the Kalachakra Initiation by Alexander Berzin
This work explains on a practical level and in everyday language the theory of tantra, the vows, commitments, and their implications.
Myriad Worlds — by Jamgon Kongtrul - The Treasury of Knowledge - Volume 1
Describes four major cosmological systems found in the Tibetan tradition - those associated with the Hinayana, Mahayana, Kalachakra and Dzogchen teachings - each more subtle and profound than the last.
Highest Yoga Tantra - An Introduction to the Esoteric Buddhism of Tibet — by Daniel Cozort
This extraordinary book clearly outlines and discusses the methods for transforming both body and mind through the highest forms of tantric practice.