Has an author successfully refused to repay a book
publisher's advance if the publisher decides not to publish the
author's book?  Book publishers often give authors an advance prior to
publishing their book.  Down the road, if the publisher decides not to
publish the author's book, must the author return the advance money? 
Is there any legal precedence for an author not having to pay back the
advance fees?

This may be of interest:

"Advances may not be offered to first-time authors; each publisher has
a different policy. Advances are made against future royalties, and
paid in installments. If an advance is offered, Carol [Luers Eyman]
suggested accepting and noted that you usually do not have to repay it
if your book does not sell. If you back out and never finish the book,
you do have to repay the advance."

http://www.stc-nne.org/Noreaster/march04/meetings.htm

It depends *completely* on the contract that the author and publisher signed. 
If the publisher refuses to publish the book for any reason that is
stipulated in the contract, no matter how subjective, the author
looses.

For example, most contracts allow the publisher to reject the
manuscript on the basis that it doesn't meet editorial standards. With
such a clause, it would be very difficult for an author to argue that
the publisher didn't have a right to reject the manuscript. (And to
get such a clause removed from a contract would be difficult...it's
industry standard.)

On the other hand, unless the advance is quite substatial, the
publisher isn't likely to sue for the advance if the author doesn't
return it. However, not paying back an advance may give the author a
bad rep with other publishers.

Kriswrite