One of the books I often find in my hands and one of the few I have ever deemed worthy of laminating by hand for containing the following words, I highly recommend it:
"At the core of Yoga is the realization of the trascendental Reality itself, however it may be conceived. This aspect of the yogic work is not at all obvious when we watch someone perform complicated postures with great flexibility and elegance. To be sure, many Western (and Eastern) practitioners are themselves not particularly aware of the spiritual dimensions of Yoga. Without it, however, Yoga remains on the level of a pastime. The traditional purpose of Yoga, however, has always been to bring about a profound transformation in the person through the transcendence of the ego (my bold). It is therefore good to remind ourselves of the purpose of authentic Yoga."
Buy it to read on