How thick is thick?

I've been scanning historic documents, including old thick books, for the Special Collections at the library where I work. If you have particular things you're trying to copy out of the book, you can check with local libraries (public and university) and find out if they have an overhead Bookeye scanner and a book cradle or the adjustable platform. Some of those scanners are very expensive so not everyone will have one, but if they do, they might allow the scanning of pages from your book. Some of these scanners have platforms that can be raised and the book pages stay more flat when the binding isn't stretched completely.

Google images for bookeye scanner.

You can see that this one supports the book well and the lens is adjusted so it photographs each page on the plane of the support.

SRS