Custom Post Type Related to Another Custom Post Type?

I’m using custom post types for a site that lists books. Each book has certain data, including a genre which is a custom taxonomy, and an author, which is actually another custom post type.

I can hack it to work by just putting the author name or internal id into a custom field, but it won’t really be normalized.

I’d rather be able to choose which author(s) wrote a book from a list as though they are part of a taxonomy like a category.

Is it possible to relate posts to each other like that using custom post types/taxonomies?