Mark Terry’s Facsimile Dust Jackets service lets you order beautiful reproductions of book covers for 7,000-plus titles. But Terry’s website is also an amazing resource for anyone who’s curious about the way his or her favorite books looked in their original incarnations.
The classics—by Hemingway, Fitzgerald, Faulkner, et al.—are an obvious, excellent place to start. But some of the best designs are for authors (like Ben Ames Williams) whom we’ve never heard of. A good way to search is to pick some well-known surname (Wells, Jones, etc.) out of a hat and see what images come up. Every page we’ve seen so far is full of designs that are delightfully of, or ahead of, their time.