I've been hit with two of those in recent days. It definitely seems to be a scam on the rise.
Aside from the fee, it's not too hard to detect. The book club isn't real and thus has no web presence. Or it is real, but its name is being used without its consent. When I questioned the last scammer, I was referred to a website that is connected to several book clubs, but as it turns out, doesn't host online book club meetings as the scammer claimed.
The initial emails are getting more sophisticated, using the product description of a book (and extrapolations from that) to provide an air of authenticity. But that's as far as the authenticity goes. When I asked questions about how the book club operates, the scammer seemed to be using AI to formulate answers. They were easily disproven.