Mandala: The Architecture of Enlightenment
by Denise Patry Leidy, Robert A. F. Thurman, Denise P. Leidy, Shambhala Publications, Inc., 1997.

Based on an exhibition of the same name, this book surveys the whole range of Buddhist mandala imagery. The text covers the historical aspects as well as the symbolic meaning of the mandala in Buddhist practice. Wonderful illustrations of the collection which contains both two and three-dimensional mandalas.

The Mandala: Sacred Circle in Tibetan Buddhism
by Martin Brauen, Martin Willson (Translator), Peter Nebel (Photographer), Shambhala Publications, Inc., 1998.

Presents a thorough study, with sensational color photographs, of the different aspects of this traditional form of sacred art. Includes photos of the well-known Kalachakra initiation ceremony performed by the Dalai Lama.

Tibetan Mandalas
by Tatjana Blau, Sterling Publishing Co., New York, 1998.

A book of very nice line drawings, suitable for coloring, illustrating various themes and symbols found in Tibetan Mandalas.

The Wheel of Time Sand Mandala
by Barry Bryant, Harper, San Francisco, 1992.

A detailed study of the sacred Tibetan Buddhist mandala tradition. Out of Print

Yantra: The Tantric Symbol of Cosmic Unity
by Madhu Khanna (Preface) and Ajit Mookerjee, Thames and Hudson, New York, 1997.

A very complete book about the yantra. Excellent illustrations.

Islamic Patterns: An Analytical and Cosmological Approach
by Keith Critchlow, Thames and Hudson, New York, 1976.

The title says it all.

The Way to The Centre: Symbols of Transformation in Tibetan Tankas
by Willy H. Fischle, Robinson and Watkins, London, 1982. (English Translation)

A color picture book of Tibetan sacred paintings. Out of Print

The Sand Mandala of Vajrabhairava
by Daniel Cozort, Snow Lion Publications, 1996.

Unfolding a Mandala: The Buddhist Cave Temples at Ellora
(Suny Series in Buddhist Studies), by Geri H. Malandra, State Univ. of New York Press, 1993.

Describes the 12 Buddhist caves at Ellora, India, and places them in the context of Buddhist art and iconography. The cave temples, dating from the early 7th to the early 8th centuries, are interpreted as three-dimensional versions of traditional mandalas, through which the devotees walked during their worship.

The Tibetan Art Coloring Book
by J. Jamyang Singe, Harry N Abrams, 1999.

42 Indian Mandalas Coloring Book
by Monika Helwig, Hunter House Publishers, 2001.

A Handbook of Tibetan Buddhist Symbols
by Robert Beer (Translator), Shambhala, 2003.