Joseph Brown (b. 1918), Australia's most prominent and respected art dealer, who was renowned for his extraordinary civic generosity, has died at age 91. Between 1966 and 1999, Brown donated 460 works of art to public collections. In addition, in 2004, he made what was described by then premier Steve Bracks as the ''largest and most generous gift of 19th and 20th century Australian art to any Australian gallery'' - 154 works worth $30 million to the National Gallery of Victoria.