To find books and government documents in USA Libraries' collections, use SOUTHcat: USA Libraries' Catalog.
Springer Ebooks: covers technical subjects but also includes books and book chapters on technical writing.
EBSCO eBook Collection: includes books on technical writing.
ebrary: titles include technical works and books on technical writing in general and for specific disciplines.
Part of Google's library-scanning project. Only books in the public domain are shown in full text. Others may have just a citation or show selected pages from the book. Remember, you can check SOUTHcat to see if we have a book you find in Google Books if the full text is not available.