A Waterdrop from the Glorious Sea - A concise account of the advent of Buddhism in general and the teachings of the Sakyapa tradition in particular — compiled by Sherab Gyaltsen
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.
A Gem of Many Colors - The Autobiography of Jamgon Kongtrul
A rich source of information on the religion, culture, and politics of Tibet during his times.
The Teacher-Student Relationship — by Jamgon Kongtrul Lodro Taye
This essential text clearly lays out what credentials and qualities one should look for in a wisdom teacher, why a wisdom teacher is necessary, and how the relationship between this teacher and disciple best develops once it is established.