Good negotiators know the rules. Great negotiators know when to break those rules. And then there are the true master dealmakers, like the pioneering sports lawyer Donald Dell. Over the last four decades, he has fought for some of the biggest stars in the world-Michael Jordan, Jimmy Connors, Patrick Ewing, Andy Roddick, Stan Smith, and dozens of others.

Dell is tough enough to look the general manager of the L.A. Lakers in the eye and say, "We can talk about the weather or the movies or...