There’s a nice little two part piece on The Situationist which has Zimbardo commenting on Milgram’s work. Well worth a read.
“Milgram left us with a vital legacy of brilliant ideas that began with those centered on obedience to authority and extended into many new realms—urban psychology, the small-world problem, six degrees of separation, and the Cyrano effect, among others—always using a creative mix of methods. Stanley Milgram was a keen observer of the human landscape, with an eye ever open for a new paradigm that might expose old truths or raise new awareness of hidden operating principles. I often wonder what new phenomena Stanley would be studying now were he still alive.” [Zimbardo on Milgram]