The word Yoga means Union. The syllable "Ha" of Hatha means Sun, and the syllable "Tha" of Hatha means Moon. So Hatha Yoga (or Union with the Sun/Moon) is really more about a particular way of alighting yourself with either of those two Cosmic influences as a way for experiencing a state of mental or emotional centeredness. A lot of this has to do with the phenomenon of Revelation and how this effects us all on a psychological level. Centeredness allows us to experience a glimpse of timelessness.
For me, personally, much of what I learned about the subject of Yoga came through reading the articles at the Isha Archives. But try to keep in mind the fact
that what really works is usually hinted at, and not explained in some way that can be easily be understood. Much of what I learned was through trial and error. My reason for mentioning the Hatha Yoga part was simply to get you pointed in the right direction.