When Edward Thomas joined the Houston Police Department in 1948, he could not report for work through the front door.

He could not drive a squad car, eat in the department cafeteria or arrest a white suspect.

Walking his beat, he was once disciplined for talking to a white meter maid.

Officer Thomas, who died on Monday at 95, was the first African-American to build an eminent career with the Houston Police Department, one that endured for 63 years. By the time he retired four years ago, two months shy of his 92nd birthday, he had experienced the full compass of 20th-century race relations.

His days were suffused with the pressure to perform perfectly, lest he give his white supervisors the slightest excuse to fire him — and he could be fired, he knew, for a transgression as small as not wearing a hat.