I listened to this book and I thought it was quite fantastic, although I think it would be a little slow for many middle school students. If there are students, however - middle or high school - who are really interested in science and/or Charles Darwin, I think they would like this book quite a lot.
The book is filled with interesting information about the time period, about the theory of evolution and about Darwin, both personally and professionally. I liked learning more about him personally, as most of what I knew about him was about the science. Most of the book focused on him as a husband and the difficulties he and his wife had because he was more of a religious skeptic than she. It was interesting to follow them through the thought process.
Overall, a great book, but it will take a special reader to appreciate it.