Very shortly before he passed away a couple of years ago, the great American composer Gardner Read had a book published through Scarecrow Press -- Orchestral Combinations-The Science and Art of Orchestral Tone-Color. I haven't heard much mention of this book anywhere -- actually, none at all -- but then, I am pathetically sheltered.
The title is pretty much self-explanatory of its content -- a prosaic description of many, many examples of various combinations of instruments utilized by composers of almost every historical musical period. Snippets of scores are provided in many instances, along with commentary by Read.
I think the book falls short in just two ways: 1) I don't think it contains enough actual score reproductions of the described examples, and 2) the snippets of scores that ARE provided are pretty small (some are eensie weensie!) -- the book's page size is just 5"x8".
Other than those two items, the book is a tremendous resource, and the implications for use and experimentation with GPO is obvious.
I bought the book when it first came out, and it was pretty pricey at nearly $70 (hardbound) -- a gift from my wife (lucky me!). It's now available only in cloth-bound form for a much more reasonable $40 from Scarecrow. Here's a link for those who may want to check it out and read a more thorough description (anyone else out there have this -- or heard of it???): http://www.scarecrowpress.com/Catalo...ata=0810848147