Originally published in 1957, and reissued in paperback in the 1960s, this is basically a textbook (or supplementary reading source) for the serious study of the philosophical schools of India -- very much including the religious traditions. Radhakrishnan and Moore assembled and edited an impressive body of material, most of it in selections, with useful introductions and helpful notes. It begins with philosophical passages in early Sanskrit religious texts, and proceeds through their orthodox interpreters, through heterodox approaches (materialist, Jaina, and Buddhist), and the medieval synthesizers, and concludes with two chapters on two modern Indian philosophers, Sri Aurobindo and Radhakrishnan himself. Although the work is careful and solid, it represents a half-century-old point of view, and especially bibliographically is in places quite out of date.
The editors take for granted the long-conventional view that the recorded history of Indian thought begins with the ancient literature in Sanskrit, and that anything earlier is either irretrievably lost, or inextricably interwoven with the Sanskrit and Prakrit heritage. In the absence of extended texts (instead of undeciphered glyphs) from the Indus Valley civilization, this is still the basic working assumption, despite attempts to recognize Shiva, for example, in ancient art. The dates are open to debate, and the relationship to the fall of the Indus Valley civillization no longer taken as obvious. Still, the Sanskrit language is regarded as having entered India with invading tribes from the north, which occupied the inviting plains of northern India (including modern Pakistan), and very slowly spread over the northern part of the subcontinent. (This has historical parallels, including the Persians, Alexander's Macedonians, and a variety of later, more permanent, invaders, most recently Muslims from Central Asia.) The ancient oral literature of the "Aryas" (Noble Ones), encapsulated in the Vedas and Brahmanas, is the foundation of later developments.
Some reviewers seem to find this objectionable. They are either implicitly denying the well-known relationship of Sanskrit to Old Persian, and of both to Greek, Latin, and the Slavic, Baltic, Celtic, Germanic (and several other) languages, or they are arguing that the whole Indo-European language group originated in India. This was a view entertained in the nineteenth-century infancy of comparative linguistics.
The latter choice requires accepting that the various ancient Indo-European speakers, instead of spreading throughout Eurasia in unrelated migrations, marched north from India, over the Himalayas, and across some of the worlds most rugged terrain, and spread out, conquering as they went, and imposing their languages on the subjugated peoples.
This is possible to imagine, if militarily (and otherwise) highly unlikely. Since it presents India as the original colonial super-power, however, those who want to present India in a positive light should perhaps complain less about what is, on the whole an admiring look at the sub-continents' more peaceful (if occasionally startlingly pragmatic / Machiavellian) contributions to history.
1) The best feature of this book is: it has the actual texts of so many great works like Vedas, Upanishads, Gita etc. For this one reason itself, it is a must have book, where else will you get such a concise and precise translations of all the major Indian texts all in one place.
2) It deals extensively not only with Upanishads and other six Darshanas but also includes Arth Shastra by Kautilya(Chanakya), the famous Indian economist/politician (contemporary to Alexander). It also included Bhagvat Gita and the famous Karma Yoga, as one would expect in any Indian philosophy book!
3) It summarizes the key-features of all the seemingly different Indian philosophies Buddhism/Jainism/Charvaka/Hinduism very succintly in the first chapter. I particularly liked the seven key similarities of Indian thought on page xxiii from the general introduction.
4) Another interesting part is on page xxx where the authors argue why one should undertake the study of Indian philosophy and how should it be taken. It takes historical, political and philosophical stand-points. Again, a must read!
4) One flaw of the book is that they have kind of assumed whole-heartedly with the Aryan Invasion Theory stating that Aryans came from outside India and settled in India around 2000 bc. However, this theory is seriously debated by many contemporary scholars like Prof Edwin Bryant (PhD from Columbia, now teaching at Rutgers), Prof Klaus Klostermaier (author of many Hinduism books, one of which was assigned reading in this class too, retired from Univ of Manitoba, Canada, now teaching at Oxford, UK), Prof Subhash Kak etc. Some of these scholars maintain that Aryans were native inhabitants of India who went to other parts of the world, starting from India. But, it is still a big controvery until solid evidences are found.
5) Other problem is: on page xxix, it is mentioned that the people from the varna, Shudra (sudra), are not religiously initiated Hindus and they dont have to undergo the four Aashrams (stages) of the human-life. This is also not agreeable statement as the same Manu-Smriti which has stated this has also stated elsewhere, that one becomes Dvija(twice born) of the first there varnas, ONLY by character and not just by birth alone. It prescribes the mobility between different varnas.