Six-session yoga practices are a common commitment of highest yoga tantra initiations. The Dalai Lama endorsed these four six-session yoga practices given with the Kalachakra initiation.
This is a very clear, concise book of translations of different versions of the Six Session Yoga texts and Kalachakra including a very abbreviated version of the Six Session Yoga for days when you don't have time to do the longer versions. All in one small and convenient book to take when traveling as well.