Guru yoga is essential for the realization of mahamudra, and in the Karma Kagyu lineage, the primary guru yoga practiced is the Four-Session Guru Yoga by the Eighth Karmapa Mikyö Dorje. This volume presents newly rediscovered instructions for this practice by the Fifth Shamar Könchok Yenlak and the Ninth Karmapa Wangchuk Dorje along with the more well-known commentaries by Karma Chakme, Karmay Khenchen Rinchen Dargye, and the Fifteenth Karmapa Khakhyap Dorje. These texts give clear guidance that, when accompanied by instruction from a qualified master, will help practitioners develop the profound realization of devotion mahamudra.