Any Book of the Month Club is dedicated to the shared exploration and experience of literature. It is a chance to share and discover great books, to accidentally revisit things you've read in the past, hopefully to tease out some new ideas about what you've just read, but mostly, the point of Any Book of the Month Club is to get together with a bunch of other people who like talking about books and then talk about some books you've read lately. And eat snacks.
Bring a copy of the book you want to discuss
Come with some ideas or questions, a passage you'd like to share, etc
Invite your bookish friends
Bring snacks, drinks, or $5. Your choice.
Be a hater. It's ok and totally fine if you want to bring a book that you did not like or that pissed you off. Just don't do that thing where you say "it's a bad book" instead of just saying "I really didn't like it at all." I-statements, people, I-statements.
Bring something you read ages ago. There are not a lot of rules here, but one of them is that you bring something you read in the past month.