Isabella Walker

Bob Edwards, the host of NPR’s “Morning Edition” for nearly a quarter-century, whose rich baritone and cool demeanor imbued his radio broadcasts with authority in reaching millions of listeners, died on Saturday in Arlington, Va. He was 76.His death, at a rehabilitation facility, was from heart failure and complications of bladder cancer, his wife, Windsor Johnston, said.Mr. Edwards, a Kentucky native who knew from an early age that he wanted to be in radio, joined NPR in 1974, during the Watergate hearings. That year, he became a co-host of “All Things Considered,’’ the public broadcaster’s signature evening newsmagazine of interviews,…