Mindfulness With Breathing - A Manual for Serious Beginners by Buddhadasa Bhikkhu
The author provides practitioners with penetrating insights into the canonical text which many believe is the most direct transmission of Shakyamuni Buddha's breath meditation methods.
The Practice of Mahamudra — The Teachings of His Holiness the Drikung Kyabgon Chetsang Rinpoche
Explanation of the five stages of Mahamudra. Probably the clearest presentation of Mahamudra meditation practice available in English.