Yes, definitely. A simple example: one tool that will be useful to compress FW is just a dictionary (or index) of English words. Instead of encoding the letters of a word, you encode the index of the word in the list, and save bits by doing so. You have to pay an up-front cost to encode the dictionary itself, but it should still be worthwhile overall, even for a single novel. Now when you compress two novels together, you get the benefit of the dictionary for the second novel without having to repay the upfront cost.