"As late as 1950, the National Association of Real Estate Boards' code of ethics warned that "a Realtor should never be instrumental in introducing into a neighborhood... any race or nationality, or any individuals whose presence will clearly be detrimental to property values." A 1943 brochure specified that such potential undesirables might include madams, bootleggers, gangsters--and "a colored man of means who was giving his children a college education and thought they were entitled to live among whites."