Hey Neeraj, this is my first post and thought I’d try to help. Not sure if you are asking about just general Essential Reading on composition etc, but if that’s the case, Jon has a great Reading List section here:
Hope that helps, I haven’t really dove into these texts, but just by listening to Jon talk about them and how they have shaped his train of thought, analytical mind, and teaching approach they must be wonderful. They are kind of expensive though, has anyone found a good website where you can get them maybe used for cheap other than amazon?
As far as I know, the best place to get those books at a discount is either used on Amazon, or the other option, is finding them in a local library in world cat.
I’d like to add that Schoenberg’s books are Google-able.
Still PDF isn’t the best option…
Best of luck