For some reason, Amazon hasn't managed to carry over reviews from earlier editions of Mircea Eliade's "Yoga: Immortality and Freedom" to this 2009 edition from the Princeton University Press MYTHOS and "Princeton Classics" series; there are, I think, seven, for various printings under different imprints. They are generally quite enthusiastic, reflecting the largely favorable response the book has produced over the decades. (Many complaints -- not all -- on Amazon and elsewhere seem aimed more at the kind of book it is, rather than its particular contents.) The present edition differs from earlier versions (those since 1969) only in cover art and the presence of a fourteen-page introduction by David Gordon White.
Originally published in 1954 as "Le Yoga. Immortalite et Liberte," the fine English translation by Willard R. Trask appeared in the Bollingen Series in 1958 (Volume 56), and was slightly revised, and the bibliography updated, in 1969. The present version is the current successor to the Princeton/Bollingen Paperback of 1970, which I read until the spine was failing, and I finally ordered a replacement early this year.
Eliade's "Yoga" is generally regarded as a landmark in Western Yoga studies, and a standard reference and point of departure for academics. It is also one of the more widely accepted examples of his "History of Religions" approach to subjects (which some people see as essentially anti-historical.) Perhaps as part of this acceptance, it has been viewed as purely the product of textual study, albeit in India.
The "New Introduction" is, therefore, of some importance to readers unfamiliar with Eliade's life, since it points out that Eliade not only studied Yoga in India with the historian of philosophy Surendranath Dasgupta, he then also practiced Tantric Yoga under the direction of an advanced teacher. Eliade never mentions this in his books on Yoga -- he was being strictly faithful to the rule that only a qualified teacher (which he was not) could pass on details of practice, and then to qualified students (not unknown readers, or strangers attending a lecture). He did mention the episode in the first volume of his autobiography (not published in English until 1981), but still withheld information on things like breathing techniques.
It is somewhat ironic that the book had to be translated from French -- not even his native Romanian, in which he had early literary success -- since his earlier Yoga studies, on which it was in part based, were in fact written in English, to fit the then-existing curriculum in India. (Dasgupta himself published -- voluminously -- in English.) At the end of World War II he had wound up as a struggling exile in Paris, until his publications brought him academic acclaim, some financial security, and later a position at the University of Chicago. (Where he was somewhat notorious for his obliviousness to mere material realities, like departmental regulations, and wars; which may help explain, if not really clarify, his confusingly, and alarmingly, pro-and-con relations with various European fascist movements.)
Although Eliade opens with an interesting Foreword noting the "absorbing story ... of the discovery and interpretation of India by Western consciousness," the opening chapter is mostly a rather dry exposition of the basic premises of Indian philosophy, quickly moving from the introductory to the technical, including the strikingly parallel contents of the Yoga and Samkhya "schools," and generally imposes a barrier to the mere seeker after "Oriental Mysticism" and miraculous powers (which latter, Eliade, like Dasgupta, believes were disdained by "true" Yogins, who were really in quest of Liberation, not power). The chapter is also helpful in understanding other books on Hindu and Buddhist thought. Later portions appear more accessible, but in fact are based on the primary exposition; so those who skip the first chapter probably will miss a lot of what Eliade is talking about.
As has often been said, this is a book for the serious inquirer -- or for someone who really needs to pass a course!
The bibliography and related discussions of text editions, etc. -- together over a hundred pages! -- are now forty years old, and therefore badly dated. Attitudes toward such things as recognizing Yogic postures in images from the ancient Harappan civilization have changed (and changed again) in the intervening years, weakening his attempts at pre-history of Yoga in India. Scattered through it is an interesting introduction to the role of what Eliade considers religious symbolism in Yoga theory and practice; there are frequent, but not always obvious, connections to Eliade's books on general "History of Religions," notably "The Myth of Eternal Return; or Cosmos and History" and "Shamanism: Archaic Techniques of Ecstasy" (Bollingen Series 46 and 76; both also translated by Trask, and available in the MYTHOS series; the 1969 edition includes additional cross-references to the translations.) Some of the comparisons may reveal more about Eliade's attitudes (like the desire to escape from 'history') than they do about either Yoga or Religion in general Still, the book remains an impressive synthesis of Indian thought on the nature of the universe, true reality, and their relation to human consciousness.