Published: Friday, April 13, 2001 6:20 a.m. EDT LEESBURG, Fla. (AP) -- Robert Aurand Moon, who invented the ZIP code for the U.S. Postal Service and was the nation's director of mail delivery services for seven years, died of a prolonged disease. He was 83. Moon, who was also known as "Mr. ZIP," started his postal career in the 1940s as a postal inspector in Philadelphia and Chicago. It was around that time that he began working on his idea for a Zoning Improvement Plan, said Barbara Moon, his wife of 52 years. Postal records show July 1, 1963, as the first day the Directory of Post Offices was issued using ZIP code numbers. After retiring in 1965, Robert Moon went to Washington D.C. in 1970 to become director of delivery services. He would keep that post until 1977, when he retired again and moved with his wife to Zellwood, northwest of Orlando. While in Florida, Robert Moon volunteered for Meals on Wheels in Orange County, the Zellwood Methodist Church and Florida Hospital Waterman in Eustis. Robert Moon, who died Wednesday at the Leesburg Nursing Center, is survived by his wife and sisters Jean Moore of Raleigh, N.C., and Mary Katherine O'Brien of Bridgeport, Conn. Funeral arrangements were being handled by the National Cremation Society in Fruitland Park (ZIP code 34731).