Actually, I like this question because now I can remember a lot of dear friends.
When I first thought about this questions, a few short stories came to my mind I wrote for my two best friends as birthday presents nearly 20 (really?) years ago. One is a crime story about a murder in a university library and the other is a story about a Russian ballet dancer. Of course, these short stories have never been published.
Another book that reminds me of someone is „Grüß den Kanzler von mir“ by Natalia Nikolajewa.
Natalja Nikolajewa lives in St. Petersburg. Her daughter Vera has left the city that celebrates its 300th anniversary this year (2003) in 1995 and lives in Berlin now. Since then the mother has been writing long letters to Vera talking about her life, her neighbours, friends and other people. She writes about sorrows and happiness. Thus, impressive pictures of the Russian every-day-life are created.
Well, I know Vera from my years in Berlin and I have also been in St. Petersburg some years ago.
Of course, there are many other books that remind me of somebody because often a friend or a relative recommends a book to me and then I start reading it and think of this person.