Q. I was reading about the new “Mad Men” exhibition at the Museum of the Moving Image, and I got to wondering: When did blacks manage to break down the barriers on Madison Avenue and become ad executives?

A. By the early 1950s, more than 40 black men were employed in “special markets” for American corporations, according to “Madison Avenue and the Color Line: African Americans in the Advertising Industry,” by Jason Chambers.

Some, like Moss Kendrix of Coca-Cola, helped create advertising approaches to blacks. Sometimes, their work consisted of keeping outright racism out of ads. A pioneer, David J. Sullivan, ran his own consulting firm, Negro Market Organization, on Fifth Avenue in the 1940s, and his dos-and-don’ts articles in the trade press spotlighted offensive marketing.

Mr. Chambers highlighted several black advertising men who struggled to open doors in the 1940s and 1950s. Among them:

Edward Brandford, a Cooper Union graduate and commercial artist, with two partners, Barbara Watson and Mary Louise Yabro, organized the first modeling agency for African-American women in 1946 in Manhattan; he followed it with his own ad agency. Unfortunately, companies eager to hire his models had little interest in his guidance. Most thought that all they had to do to reach black consumers was change the race of the models in their ads.