It's been ages since I've read this, so I'm rereading a number of passages as we read the letters. I'm finding an excellent companion to the letters. Tomalin's research is carefully documented with many annotations. There are 2 sections of illustrations, including portraits, sketches and paintings of various locations, and plates from early editions of the novels.

There is also a family tree, which is invaluable, reminding me of birth years, and keeping me straight on all the familial relationships. :-)