|In the 1980s, photographer Robert Mapplethorpe became a prominent figure in New York City's sub-culture of artists and performers. His younger sibling, Edward, a budding photographer himself, grew up idolizing his mysterious and exciting older brother. But the two parted ways in a nasty split, which sent Edward into a downward spiral motored by drug addiction. He rebounded, and is now creating his own artistic legacy. Serena Altschul reports.