Gee, and I thought I was the only one!  For my book, _Mark Twain in the St.
Louis Post-Dispatch_, I used the _New York Times Obituary Index_ for many
promising leads, one of which took me to the _Chicago Tribune_.  I was
finally able to state that he died in an Oak Forest, Illinois, poorhouse in
1917, although I would have liked to have confirmed this information with a
death certificate.

Anyway, I have found the _Obituary Index_ invaluable and heartily recommend
it as a starting place for biographical questions.