Do you actually have permission to post whole books? Don't they have copyright? Or did you buy the copyright?
That was a great book about Chopin.. Maybe I'll print it some day.
All books published more than 50 years ago can be copied for free. You can even scan the entire book and just put it up. By some reason unknown for me, it is 70 years (in most countries, in Russia it is 125 but they do not seem to care anyway) for sheet music. That is the reason sheetmusicarchive.net exists. They just copy stuff older than 70 years and put it up. However, they claim right to the ownership of the copied file but I doubt they can do that. What you basically could do is order their entire CD and put up a competing site.
We actually had several books up and many such things will be recreated for the old site. You can always make a suggestion and we take that for consideration.