My dead young composers, I think it is time to list resources I enjoy reading and am reading. I will start with more accessible to new composers then go to most advance ones. Every composer, under their toolbelt, should have firm understanding tonal harmony. While the millions of books on the market, it is probably difficult to decide which one to use. This is where your undergraduate course helps you. Professors have thier prefence. Mine used "tonal Harmony" However, if you want to get jump, I suggest two books: Fux treatise on species counterpoint, and Tchaikovsky treatise on harmony. Schoenberg also wrote two books on harmony. Be warned: Schoenberg book on Harmony is like reading book on philosophy. Traditional harmony is fine, but we are currently in modern era where that pushes the boundaries. Thus, book on 20th century harmony should the follow up. There are two books that go through this! I think Peter is going through one. He would reccomded that one. I have that one. And I would agree with his assestion about it. I would also suggest picking up book on Alan Forte and "The music of Bela Bartok" Understanding musical style is important as writer. Therefore, Charles Rosen books "The classical style" and "The romantics" are a must. He links Bach to each period. Speaking of Him, he wrote about Sonatas: Sonatas forms. (I hear there are 3 vol set about sonatas, but his book is more concise). Now to onto musical forms: Analyzing Classical forms and Sonata theory. Both are great books. But start with Schoenberg book on composition. I hope this well you. Also, score study. Share your works as you learn. And choose the best path that works for you. Orchestration is the final step! Rimsky-Korosky, Adler, Brant.