There are auditions and then there are the ones that the people present for them carry for the rest of their lives — the moments when the door opens and something walks through it that the room was not fully prepared for, that rearranges the air and the expectations and the entire trajectory of what everyone present thought was going to happen, and that produces in the people watching the particular, irreversible certainty of witnessing something that will matter long after that day is over.

The audition that brought Mary Tyler Moore into The Dick Van Dyke Show was one of those moments — and the man whose name was on the door, the man whose instincts about talent and chemistry and the specific, unnameable quality that makes television come alive had already proven themselves worth trusting, knew it before she had finished her first reading. Dick Van Dyke has returned to that moment across sixty years of interviews and tributes and retrospectives with the consistency of someone describing something that left a permanent impression — the young actress who came in for Laura Petrie and demonstrated within minutes not that she could play the part but that she somehow already was the part, that the intelligence and the warmth and the precise, completely unforced comic timing she brought into that room were not qualities she had developed for the audition but qualities she simply had, had always had, would always have, and that the show he was building was going to need in ways he had not yet fully understood until she walked in and made them suddenly, completely clear. The producers felt it. The writers felt it. The network people in the back of the room felt it. And Dick Van Dyke — who has spent his entire extraordinary career surrounded by extraordinary talent and who has never been a man given to easy superlatives — looked at Mary Tyler Moore in that audition room and understood immediately that what he was watching was something the television audience was going to love for a very long time.