A Lamp to Illuminate the Five Stages · Teachings on Guhyasamaja Tantra — by Tsongkhapa - translated by Gavin Kilty (Library of Tibetan Classics - Volume 15)
Covers the subtle human physiology of channels and winds along with the process of dying, bardo and rebirth.
The Book of Kadam — Attributed to Atisa and Dromtonpa · Library of Tibetan Classic - volume 2
This work is a landmark in the study of Tibetan culture in general and Tibetan Buddhism in particular. Undisputedly one of the greatest works.