Memory is a turning point in the Vorkosigan novels by Lois McMaster Bujold. It's also one of my two favorites (the other is A Civil Campaign). A two-sentence summary with a minimum of spoilers would go something like this: Our Hero experiences medical problems that force him to leave his job. Bad things happen to a friend of the family, and in trying to solve the mystery of what happened, he discovers new purpose in life. That's a gross oversimplification, of course. And, because of its position in the series, it's decidedly not a good starting place.
Here are some of the interesting and relevant themes, without worrying about the spoilers:
Learning to accept health problems with potential lifelong consequences
Impulse and bad decisions
Celebrating a birthday, or attempting not to (30 in his case)
Going to where you grew up to find things have changed so much you don't recognize them
Watching friends fall in love and marry around you, when you have nothing on the horizon
Discovering how important an old family friend is when it's almost too late
Redefining self and making a new life
I now wish I'd been taking notes while I read. I have never yet managed to do that, but there are a couple of authors that make me want to. Or to have multiple copies of the books, so I can highlight and write in the margins of one...