Khenchen Appey Rinpoche (1926-2010) was widely respected as one of most eminent teachers in the Sakya tradition of our time. Belonging to the generation of masters who received their full training in Tibet, Appey Rinpoche was instrumental for the transmission of this knowledge to the new generation of teachers. He was the founder of the Sakya College in Dehradun, India, and of the International Buddhist Academy in Kathmandu, Nepal, and initiated the digitisation of hundreds of volumes of the Sakya tradition. In this teaching, Khenchen Appey Rinpoche provides a brief yet profound commentary on the famous mind training text from the tradition of Atisha. It offers instructions for the cultivation of bodhicitta, the heart of awakening, on both the ultimate and the conventional levels. Full of practical advice from a master who embodied the teachings, this commentary is of immense value for students at all levels of practice.