I just write it down with a pencil on paper by year, month, title, and author. Occasionally I add a 🙂if I especially liked it, something like this 😬 if it scared me or creeped me out, or ☹️ if I was disappointed. I started keeping track in June of 2017. Since then I’ve read 390 different books. I’ve read a few series of books more than once.