Together these represent a very comprehensive guide to the best resources for art research. Scanning the Tables of Contents will enable you to identify the sections you should examine, and the more detailed index in each volume will lead you to anything you might have overlooked.
If you are dealing with stained glass, ivory, metalwork, or textiles, look here! These are great examples of scholarly bibliographies. They can save you a lot of time finding out what has been written on your topic.