The A. B. Simpson Historical Library, which is housed at The C&MA (U.S.) National Archives in Colorado Springs, CO, is the most complete collection of Alliance-related books and periodicals (some are in languages other than English). The collection is non-circulating and the library does not have an online catalogue. Contact information is available on The C&MA National Archives site (you'll need to create a MYCMA account); look for it under Advanced Research.
The C&MA collection of the Ambrose Library (Ambrose University, Calgary, AB) is almost as extensive as that of the A. B. Simpson Historical Library, and many of the items in it are available to borrow. If you're not a current student or employee of Ambrose, you may sign up for a Community Borrower account to borrow print books from the collection. More information about the Community Borrower account can be found at the bottom of the Library Staff & Policies page.
WorldCat is the most comprehensive library catalogue in the world. You can look up virtually any Alliance title on it and it will give you a full description of it. For each book that you search for, the "find a copy in the library" feature will show the nearest libraries with copies available for loan.