In the West, yoga tends to be regarded as an exercise thing, but the tradition is much richer and deeper than that. Anyone who would like an exhaustive (and exhausting) overview of that panoply might want to check out Georg Feuerstein’s book The Yoga Tradition: Its History, Literature, Philosophy, and Practice.
This is not the book to turn to if you want to know how to do various asanas or if you want a concise description of the various yoga schools. It’s not even the right book if you want a fluid translation of Patanjali’s Yoga Sutras with commentary. My Sanskrit is nonexistent, but having read more than one translation of the sutras, I can say confidently that Feuerstein did not concentrate on style or flow in that particular translation. I’m unfamiliar with many/most of the other texts he translates, but my sense is that he is more of a literalist than a stylist, which may be fine for scholars, but tends to wear out and confuse the regular reader.
I think I am glad I read it, but I’m not entirely sure. There is some truly weird stuff in the annals of yoga. I don’t know how or if this book will influence my own practice, but I do know more than when I started, so that’s something.