The Composer and the Novelist- Parallels in History...

The famous novelist Michael Crichton passed away in 2008 from cancer, leaving an unfinished story behind. Evidently Crichton's agent was impressed enough with this unfinished work to contact another author to ask him if he would be interested in completing it.
At first this author, whose name is Richard Preston, hesitated, obviously due to the rather unique proposal offered him; after all, how often is the work of one creative mind taken over for completion by another?
Well, how about Amadeus Mozart and Franz Sussmayr?
It appears that Mozart's last great work, his Requiem, slipped from his dying hands before he could complete it, and Sussmayr was called upon to finish this masterpiece.
There are several different stories attached to the Mozart/Sussmayr saga; for instance, how much of the remainder of the Requiem was dictated to Sussmayr by Mozart as he lay dying? or, was Mozarts' widow a primary component in the finishing of the Requiem by Sussmayr, who was both a highly skilled composer and dear friend of the fabled composer?
It is known that within a hundred days of his receiving the manuscript for completion, Sussmayr presented it to the great composer's widow.
Some historians claim that Sussmayr had studied with Mozart; however, there seems to be more weight to the reality that he had studied with Mozart's chief competitor in Austria, Antonio Salieri.
Oh-by the way; Richard Preston DID complete Crichton's last tome not too long ago...