As Alicia pointed out in the comments, you can also add graphics of book covers to your timeline or Book of Centuries. Alicia, in fact, does this in her homeschool and I've seen the results up close and personal. It's a terrific idea that combines the beauty of living books and a visual history lesson.
You can scan book covers, go to the publisher's website, or visit a search engine such as Google and click on the image search. Then print out the graphic and paste it to the timeline. Very cool!