Alex Soteros asks:

>Can you think of any artist who is both a composer and an author?>>

Friedrich Nietzsche wrote a bit of piano music, some of which is available
on CD.  Although his dalliances with composition are not quite on par with
his philosophical writings.

Peter Warlock was the pseudonym of a British music critic.  As far as I
know, his compositions have outlived his criticism.

Regards,
Bob Chen
Los Angeles, CA