How do we model classic many-to-many relationships with CQRS/DDD?
I know that both DDD and CQRS implementations and solutions tend to be domain-specific, so it may be difficult to come up with a general answer to this question.
However, let's assume we have the familiar relationship between Book and Author. This is a classic many-to-many relationship.
To me, it seems most natural that Book and Author are two different Entities that each belong in their own Aggregate Root. Thus, explicitly modeling the many-to-many relationship between them is not the way to go.
How do we model an AddBookCommand? We want to be able to add a book to our library, and also somehow state that a particular Author wrote this Book. How do we model (and persist) such a relationship?
Neither Book nor Author seem like good candidates for Value Objects...