Academic textbooks and indexes

Looking at an academic textbook I bought so I could access it quickly. "Yup, this will be useful!" And grateful for its fairly extensive index, which is much more detailed and useful than the index for a related 1970s textbook Martin borrowed for me from the uni library (I have staff borrowing rights too, but he was on the spot!). Which pretty much just indexes names. As an academic I'm expected to read textbooks as needed. Unfortunately it's a huge problem with my progressive neurological disease and has been for 25+ years now, inc during my history taught MPhil and PhD. So I'm extremely grateful for anything that can help narrow it down. Including a good index!