Robert (Bob) J. Birnbaum, 91, of Cambridge, Mass., formerly of West Hartford, died July 30. He was the widower of Barbara (Umanoff) Birnbaum. Born in New York, he was the son of the late Paul and Mildred (Braunstein) Birnbaum. He served in the U.S. Army as a lawyer and journalist in Germany. He is survived by his loving companion Hyaline Greenberg of New York, his daughters, Margot Birnbaum of Cambridge, Carol Birnbaum and her husband Adam Manacher of Cambridge, Paula Birnbaum and her husband Neil Solomon of San Francisco; his grandchildren, Daniel, Jonathan, Jordan and Mariel; his brother-in-law and sister-in-law David and Shelly Umanoff of Boynton Beach, Fla.