For the Endocrine and Reproductive Biology (ERB) block, you really don't need a supplemental book. Most of the assigned readings come from Boron. There are also optional readings that come from another book and that were posted on the portal as additional reading. I'm not sure what book those optional readings came from, but I liked that book's coverage of these topics WAY better than Boron. After the first week, I mainly read the additional readings instead of the Boron readings.
Hematology, Immunology, and Microbiology (HIM) block:
For immunology, you should get Immunobiology: The Immune System in Health and Disease. 6th ed. by Janeway, and also How the Immune System Works by Somparyac. Both of these books are recommended, and I liked them both a lot. It's best to read the Sompayrac book, which is very short and entertaining, early on in the block. Then you can focus on the denser Janeway book afterward. Just in case you're interested, Lippincott's Illustrated Reviews has also just put out an immunology book as of summer 2007. It didn't come out in time for me to make use of it during the class, unfortunately, but it might be a good alternative if you like Lippincott's books and don't like the Janeway book. If anyone reading this post has bought the Lippincott immunology book and is willing to tell me what you think of it, please leave a comment.
For hematology, no additional books are necessary. You might want to go ahead and get the Robbins path book for next year if you haven't already, because there are some very useful heme readings in there. Also, we weren't ever assigned any readings from the Hematology for the Medical Student book that we bought last fall, but I read several chapters out of it and found it to be a very helpful book for heme. Some of the heme articles we were assigned to read weren't as good as the readings from these two books.
For micro, I had bought a book from one of the upperclassmen as my main text called Sherris Medical Microbiology: An Introduction to Infectious Diseases. 4th ed. by Ryan. That was the book used by the first two CCLCM classes, and I just read the appropriate sections depending on what topics we were covering. The new required book for my class was Medical Microbiology by Murray, but you can use either that one or the Sherris book. Whichever text you buy, I recommend also getting Clinical Microbiology Made Ridiculously Simple by Gladwin. It's a much more digestible way to learn micro. Also, if you like the Lippincott's Illustrated Reviews series (pharm, biochem), you might want to also get their micro book. The pictures and diagrams are really awesome and helpful for conceptual learning, and the Lippincott micro book goes more into the clinical aspects of the lab tests than either of the other micro books I bought did.