I’m listing these two books together, as I’m constantly asked which books a beginning orchestrator should read. Here is my perennial reply: get the Piston text first. It is clear, concise, and well-laid-out, giving you valuable, usable information in simple, memorable words. Read it many times, and try out some of the assignments. Then, when you are absolutely certain that you have the willpower, desire, and aptitude to get serious about your training, then and only then should you invest in the Adler. The Adler is state-of-the-art – but for that, you will have to pay university books store prices, even on Amazon. Get the recordings along with it, those are essential for reference.