I assume that any long-term New Yorker would know who the Collyer brothers were, but for newbies, they were wealthy brothers in the first half of the 20th century whose name has become synonymous with reclusiveness and hoarding. It's a sad but interesting story.
I was just reading a fun book called
Mess, by Barry Yourgrau
Mess & Two Fiction Reissues - Barry Yourgrau
which says that the Collyers only became so paranoid and reclusive after an assertive woman reporter connected with them, wrote them up in an article, and that started to trigger attempts to break into their Fifth Avenue house, people trying to steal money that they imagined was being hidden there. Which is even sadder.