Scholars of the Ngor Monastery belonging to the Sa skya School of Tibetan Buddhism started to compose a systematic work of theories and practices of Indian and Tibetan ma?d.alas in 1870 and finished its publication by 1894. The title of this work is the rgyud sde kun btus (Collection of the Tantras), which consists of thirty-two volumes. The work was reprinted in India during 1971 and 1972. Probably shortly after the completion of the compilation of texts at the Ngor Monastery, Tibetan artists began to draw ma?d.ala pictures according to the description given in those texts. Rev. bSod nams rgya mtsho, a former abbot of the Ngor Monastery, told once that three sets of the ma?d.ala pictures of the rGyud sde kun btus were painted. One of the three sets was reprinted by Rev. bSod nams rgya mtsho from Kobansha in 1983. Dr. Lokesh Chandra published a set of line drawings of the Ngor Ma?d.ala Collection in 1967. The set of mandala collection used for the line drawings has been reproduced in this volume. This set seems to be the second set out of the three sets. As for the third set, nothing clear is known. No one can deny that the Ngor Ma?d.ala Collection is one of the most authoritative Tibetan ma?d.ala collections.