Mad Men is a show know for its style, so youd imagine a fair amount of thought went into creating the branding for Sterling Cooper. Well not quite enough, it would appear. Font designer Mark Simonson wrote a blog recording all the various typeface issues within the show, referencing a number of fonts used that didnt actually exist back in the 1960s. Once of the more notable errors, it turns out, was with the Sterling Cooper sign. The font used is Gil Sans, and Simonson points out that while this did exist, it wasnt widely-available nor popular in America until the 1970s.