As a composer, there's only a few books I feel the need to keep within arm's reach of me. Ok, I lied...there's only one, and this is it. I have the classic outdated books by Berlioz and Piston, and they're certainly nice to look up more period practices or odd instruments no longer in use, but this is the book. To put it this way, my keyboard doesn't live on the keyboard shelf, this book does.