You finish a book, recommend it to a friend, and then struggle to remember the part that made you recommend it. Or you return to a half-read novel and cannot remember when you last picked it up. A reading log gives those loose details a place to live.
If you are wondering how to keep a reading log, start with a small record: the book, your current place, the date, and one thought worth keeping. You can use paper, a spreadsheet, or an app. The useful system is the one you can update without turning the end of every reading session into homework.
Decide what you want your reading log to answer
Before choosing a tool, pick the question that brings you back to your record. Do you want to remember what you read? Find passages for a book club? Notice whether you make time for books during the week? Each purpose calls for slightly different details.
For a memory aid, record titles, authors, completion dates, and a short reaction. For discussion or study, add a page reference and a note about the idea. For a routine, record the days you read and, if useful, how long you spent.
Choose one main purpose at first. You can add fields later when you have a reason to use them. A log does not need a rating, genre, publication year, purchase price, and detailed review for every book unless those details help you answer your question.