Custom Taxonomy Slug

When creating custom post types and custom taxonomies I always seem to have trouble getting the rewrite slug to be what I want.

If I have a custom post type called Books
and a custom taxonomy called Authors

I end up with this
http://www.mysite.com/books/mybook – this is good
http://www.mysite.com/authors/john-doe – this is not what I want.

I want this for the taxonomy
http://www.mysite.com/books/authors/john-doe/ – how do I make this happen.

Basically how do I put the custom post type in front of the custom taxonomy in the slug/url