Show of the week: Mad Men

“Who is Don Draper?” is the opening line of Season 4 of AMC’s outstanding drama about a 1960s advertising executive—and it’s a nice summation of the question that’s posed by the entire series. As of 1964, Draper (Jon Hamm) is a divorced dad, the mercurial heart of a struggling new agency, and, according to a disastrous Advertising Age profile, a “handsome cipher.” In executive producer Matthew Weiner’s hands, his ongoing effort to define himself reflects America’s own turbulent identity crisis during that time. Sunday, July 25, at 10 p.m., AMC