I'm unashamedly a book worm. What a treat to wander into a bookshop, choose whatever takes your fancy and devour it! In a library now which is a dangerous place for me. My students are too because nearly every one of them have asked for recommendations on yoga books, so here goes:
I completely get this desire to read up on something that you're about to dedicate hours of your life towards.
Before I got onto my inversion junkie stage of my yoga journey I was afraid that if I said 'I do yoga' people would know what that ACTUALLY meant or would assume that I was some Siddhi-manically-crazy person. Which is no bad way to be- but you've got to make sure you agree with what you're doing before you go and invest your whole life into it!
So if you're at a similar stage where you're like, "sounds good...but I'm not sure what this yoga thing actually is..." to save you doing what I had to do (downloading the reading lists of all the teacher training courses that I could find and getting the books for Christmas, reading them and subsequently pestering masses of teachers about it) can I just point you to 2 books that I think will start you off fairly well?
Firstly read this edition of the Bhagavad Gita. Mainly for the introduction which goes through the basics of hinduism and indian culture that you need to have as a foundational understanding. Then for the actual upanishad- the authors introductions again make things quite straightforward.
Secondly, if you have the energy and are a true book worm read this. It is nice and critical, I'd say the chapter on types of yoga is very, very good. Any of the physical stuff you're doing is Hatha yoga and don't be scared by the powers and acsetic side of that! If you can't stomache that heavy tome I'm summarising part of it in a blog but as it began to become an essay- which is a skill that I am poor at- I decided to summarise it in a diagram. This you will have to wait a while for as it is work in progress as I am currently studying for Pregnancy Yoga.
So happy reading book worms, as I am continually reading up more and more about yoga, Buddhism and all this area of knowledge that I generally lump in my head as 'interesting spiritual takes on life' I will write little reviews.