Co-Authors? How Successful Are Partnerships on Books--and What Are the Pitfalls to Watch Out For?

When my first book was contracted by a publisher, I was assigned an editor who also wrote for Men's Health magazine.  This editor, being a writer too, knew how scary it was to have a first book.  I knew very little about how to structure a book; my editor showed me the ropes.

Not long after that book got published, I got a call from the same editor.  Would I like to partner up with him on authoring another book? 

We proposed a topic that we were both passionate about.  An agent got interested and we signed a contract. 

The agreement for our co-author partnership was very like our author-editor relationship for my first book.  I would provide the "talent" or the content.  My co-author would help me shape it.  It was a journey we'd travel together--one of us deciding where to go, the other deciding how.