A small booklet by Khabgön Phakchok Rinpoche of the Noble Wisdom of Passing Sutra (Daka Yeshe Do) translated into eight languages.
In this beautifully concise Mahayana sutra, that is merely a page long, Buddha Shakyamuni summarized the five indispensible key points that every Bodhisattva must cultivate and master before they pass beyond sorrow.

These five points ~ impermanence, great compassion, freedom from reference points, non-existence, and Buddhahood ~ are universally applicable to any Buddhists on the sutra path of Mahayana and the tantric path of Vajrayana.