Yoga Unveiled

If you are looking into gathering some great knowledge on yoga and its history and philosophy this is an amazing DVD.
Not easy to get as you need to either order it online or, for example, I found it at the Jivamukti studio in New York; possibly some well stocked yoga studios might have it.
Is a little pricy but it is totally worth the money , it will give you a great insight on yoga through the testimonials of some amazing yogis spread throughout 2 DVDs of 3hr15.
You can sit back and relax and learn a lot:)
http://www.yogaunveiled.com/