Excellent for any composer
Being a professional composer, this book shall not be missed whilst the orchestration or writing of compositions. It offers a very comprehensive overview of instruments, how each of them works (ranges, fingering, keys etc.) and in what order they belong together onto the manuscript paper.
Each chapter is clear and easy to view. This is not a flowing text like some of the other orchestration books, but offers much more of a large and in-depth overview to the ways in which instruments work.
I found it and still find it an invaluable source of information.