Not for Happiness - A Guide to the So-Called Preliminary Practices — by Dzongsar Jamyang Khyentse

Everything an aspiring practitioner needs to get started the Ngöndro practice.

Ngondro Commentary - Instructions for the Concise Preliminary Practices of the New Treasure of Dudjom

A practical and accessible guide for students to use in directly engaging the preliminary practices, which establish the foundation for the entire Vajrayana path.

The Dzogchen - Innermost Essence Preliminary Practice — by Jigme Lingpa

This is not only a preliminary practice but actually provides a complete means in itself for attaining the fully awakened state.

The Gem Ornament of Manifold Oral Instructions — by Kalu Rinpoche

This book contains fourteen chapters dealing with aspects of the path to enlightenment as explained by His Eminence Kalu Rinpoche. The perspective is Buddhist in general, with teachings from the scriptures of the Theravada, Mahayana, and Vajrayana traditions.

Ninth Karmapa, Wanchuk Dorje's Ocean of Certainty — by Traleg Kyabgon Rinpoche

Traleg Kyabgon Rinpoche's commentary to the sixteenth century work Pith Instructions of Coemergent Wisdom, Entitled the Profound Essence of the Ocean of Certainty , by the Ninth Karmapa - Wangchuk Dorje.

Entrance to the Great Perfection - A Guide to the Dzogchen Preliminary Practices — by Cortland Dahl

Blending contemporary and traditional perspectives, this groundbreaking work offers guidance on the profound foundational practices of the Great Perfection.