There are moments in the history of American television that the people present for them understood immediately as something different from what ordinarily happened in audition rooms and casting sessions and the routine business of assembling a cast — moments when someone walked through the door and the quality of the air in the room changed, when every person present felt simultaneously the particular excitement of encountering something genuine and the professional certainty that whatever was about to happen was going to be worth remembering.

The moment Mary Tyler Moore walked into the audition for The Dick Van Dyke Show was one of those moments, and the man whose name was on the door has spent the sixty years since describing it with the particular warmth and the particular precision of someone who understood what he was seeing as it was happening and has never stopped being grateful that he was in the room to see it. Dick Van Dyke has told the story many times across many decades — the young actress who came in for the role of Laura Petrie and demonstrated within minutes that she was not merely right for the part but was somehow already the person the part had been written for, that the warmth and the timing and the specific, completely natural quality she brought to the reading was not a performance but simply who she was — and the consensus in that room, from the producers and the writers and the man whose instincts about talent had already proven themselves worth trusting, was as immediate and as complete as any in the history of the medium. Nobody disagreed. Nobody had a reason to. Mary Tyler Moore was simply, self-evidently, undeniably the best person in any room she ever walked into — and the man who watched her walk into that one has spent the rest of his life making sure everyone understood what he saw.