[4][5] Yoga is a group of physical, mental, and spiritual practices from ancient India, forming one of the six orthodox schools of Hindu philosophical traditions.

The book became an international best-seller; it has been translated into at least 23 languages including Chinese, Czech, Hebrew, Japanese, Hungarian, Portuguese, Russian, and Thai[11] and has sold over three million copies.

[LoY 7] Each asana is named in Sanskrit with its etymology, graded, and described separately with two or more pages of text and monochrome photographs of Iyengar.

[13] Yehudi Menuhin, in his foreword to the book, wrote that "Whoever has had the privilege of receiving Mr Iyengar's attention, or of witnessing the precision, refinement and beauty of his art, is introduced to that vision of perfection and innocence which is man as first created — unarmed, unashamed, son of God, lord of creation — in the Garden of Eden".

[LoY 12] The scholar of religion Andrea Jain observes that the book "prescribed a thoroughly individualistic system of postural yoga",[14] one that was "rigorous and disciplined",[14] requiring "belts, bricks, and ropes".

[14] She quotes Elizabeth De Michelis as writing that it "instantly became the global standard reference on modern yoga as a body practice.

"[14] Jain argues that Light on Yoga had the particular attraction for a consumer audience that its clear stepwise instructions enabled them to practice at home, and to read about the "biomedical explanations of each posture and its fitness and health benefits.

For example, she explains, the triangle pose and the sun salutation "don't appear in any ancient yogic text" but were put together into a method by Iyengar's brother-in-law and first teacher, Krishnamacharya.

[1] Derek Beres, writing in Big Think, called the book "wildly popular" and "essentially the bible for yoga practitioners."