Sanskrit text and English translation of 20 Yoga Upanishads. The translator, G Srinivasa Ayyangar, has closely followed the Sanskrit commentaries of Sri Upanishad-Brahman-Yogin who is the only one so far known to have achieve the unique distinction of having written a commentary on all the 108 Upanishads.
A rare and Invaluable resource from the The Adyar Research Centre, Chennai. Unlike some more literal Sanskrit translations this is free flowing and digestible for the western reader despite the subject matter at times being very esoteric and advanced. I know this book will be returned to again and again as my practice develops.