That's how I got through War & Peace the first time; someone with really nice handwriting annotated mini paragraphs worth of notes in the margins and they really helped me get through the book.

If you want some recommendations for professional annotations, I loved The Annotated Alice. It has annotations for both Alice in Wonderland and Through the Looking-Glass in a single copy. Well-researched, probably because it went through several editions each time the publisher found new information to add to it.