"The Yoga-darshana includes the Yoga-sutras of Patanjali, and the ancient commentary thereon by Vyasa. The Yoga-sutras of Patanjali are the classic formulation of the science of meditation. This science is called raja-yoga, the kingly yoga, because through it one learns to rule one's own mind. Human psychology is analyzed from this standpoint, and the resulting system of meditation is delineated, all in 195 terse sutras. A sutra is a "thread" of thought, designed to aid the memory.

These brief statements alone do not give the full system. This must be gotten from a commentary. The most authoritative commentary is that by Vyasa, but it is also the most difficult. This is due to its obscure terminology, which will long remain problematic simply because English has no equivalents, and its archaic syntax. For many years, no one could translate it. This task was first accomplished by Ganganatha Jha.".

"Ganganatha Jha was the greatest translator of darshana texts in modern times. The texts of the darshanas, the six schools of Indian philosophy, are written in a specialized technical style. He first translated the Yoga-darshana in 1895, then went on to translate original texts of all the other darshanas.

In 1934 he thoroughly revised this translation, making it "as good as it lay in my power to make it." His mastery of archaic darshana syntax makes this what may still be regarded as the best translation of this difficult text."--BOOK JACKET.