This is a good survey of the study of the p53 gene: one gene which turns out to have quite a bit influence on whether or not cancer develops in the body. It features some science, some history, some characters, and generally clear explanations of exactly how the science all works. It’s evident that it’s written by a journalist and not an expert, but that’s usually the perfect level for a casual reader anyway.
Now, if you don’t find cancer and how it progresses interesting, this will probably be lost on you. But if you have any interest, the background covered here is quite important to understanding cancer as a disease. It covers stuff like the “two hits” theory, why some children can be born with cancer, etc, etc. Enjoyable might be the wrong word for it, but I found it easy to read and informative.