“I used to wonder how you were so expertly servile.”

On Mad Men, James Wolk’s eager-to-please ad man Bob Benson—a sort of golden retriever in an impeccably preppy suit who was always ready with an extra cup of coffee or a deli platter for a funeral—offered one of the season’s most hotly discussed mysteries, second only to whether Jessica Paré’s Megan Draper would be murdered. Theories were rampant. Was the perpetually chipper up-and-comer, who inexplicably seemed to materialize at SCDP (later renamed SC&P), a spy from a rival agency, an undercover reporter, Don’s love child, or a government agent?

Last week’s episode, “Favors,” seemed to indicate that Bob was gay, as he appeared to make an advance at Pete Campbell (Vincent Kartheiser) by gently touching his boss’s leg with his own and seemingly making a declaration of his love. When I asked Mad Men creator Matthew Weiner at the Academy of Television Arts and Sciences panel I moderated last weekend whether Bob Benson was gay, he demurred, saying what passed between Bob and Pete didn’t necessarily indicate that. So, then, the question hovers in the air like smoke from one of Don’s cigarettes: just who is Bob Benson?

But Bob Benson isn’t a spy, an undercover reporter, or a G-man. (Nor is he Don Draper himself, as some have confusingly guessed.) The truth is far more mundane, in a way: Bob Benson is anyone he needs to be.

In this week’s episode of Mad Men, “The Quality of Mercy,” Bob’s secret history came tumbling out from a most unexpected source. Headhunter Duck Phillips (Mark Moses) discovered, when tasked by Pete with finding leads for Bob, that Bob’s personnel file “might as well be written in steam.” Every bit of information we’ve learned this season about Bob—the blue-blood connections, the dead father, his work experience, etc.—was a fiction cleverly created by a cunning social climber, one who wanted to leave his West Virginia roots behind and reinvent himself as a slick go-getter.

Does that sound like anyone else we know?

There are clear shades of both Patricia Highsmith’s Tom Ripley character—most recognizably embodied by Matt Damon in Anthony Minghella’s 1999 film The Talented Mr. Ripley—as well as allusions to Jon Hamm’s Don Draper, who landed his job in advertising simply by pestering Roger Sterling (John Slattery) until he gave in to Don’s enthusiasm. Like Bob, Don has a sordid past at odds with the polished executive the world sees. Unlike Don, Bob didn’t assume anyone’s identity to fulfill the deception. He may have lied, manipulated, and cajoled others around him, but he didn’t commit any crimes of which we’re aware.

Bob Benson is a younger shadow of Don Draper, unencumbered by the wartime service, the mistaken identity, or the theft that Don perpetuates by stealing another man’s life. He’s a “hillbilly” who fast-talked his way into a job at the agency and attempts to climb the ladder of success by ingratiating himself with everyone along the way, finding their vanities and their weaknesses. (We should also be reminded here of J. Pierpont Finch from How to Succeed in Business Without Really Trying, which coincidentally starred Mad Men’s Robert Morse.) We learn that Bob was a manservant for three years to a senior vice president at a blue-chip firm and traveled to Europe with his employer on the Queen Elizabeth ... until he “disappeared with an electric pencil sharpener and their entire Christmas card list.”

What Bob achieves is a masterful reinvention, an exchange of one life for another, believing inherently that identity is something fluid and temporary; it doesn’t define us forever. A manservant can become an accounts man, a hillbilly a blue-blooded Manhattan prince. (“You complimented my tie,” Bob tells Pete. “It was the happiest day of my life.”) But the truth, as Don inherently fears, has the potential to always overtake us in the end, whether it’s Sally (Kiernan Shipka) discovering her father’s adulterous flaws, or Pete learning of Bob’s true identity, or Peggy (Elisabeth Moss) realizing that her former mentor is a “monster.”

For his part, Pete doesn’t do what is expected. Rather than expose Bob Benson for a fraud, Pete realizes that Bob is far more valuable to him now that the truth is out there. He doesn’t react sentimentally or emotionally but intellectually. It’s less an act of mercy than a shrewd one that benefits Pete as much as it does Bob:

“It terrifies me what you could do in a day,” Pete says as Bob pleads for a stay of execution. “No, Bob, you’re going to get the benefit of the fact that I’ve been here before. I don’t know how people like you do it. You’re certainly better at it than whatever I do. But I would like to think that I have learned not to tangle with your kind of animal.”

Pete, of course, has been here before with Don Draper and been forced—out of expediency, respect, or begrudging admiration—to keep Don’s secret to hold on to his own career trajectory. But this time, Pete knows he can own Bob and that by relinquishing any punitive action (“Where you are and what you are is not my concern,” he says. “I surrender.”), he can use Bob as a cat’s-paw. Or he can attempt to, anyway, which is what that huge sigh of relief is about when Pete leaves Bob’s office after confronting him.

The clues to Bob’s identity were concealed masterfully throughout the sixth season, right up to the reveal. Bob’s desire to help Pete secure a nurse for his ailing mother leads to Mrs. Campbell hiring (and then falling in love with) Spanish aide Manolo (Andres Faucher). (Bob’s heretofore unseen ability to speak Spanish was a bit of a shocker this week, though he must have been colluding with Manolo in some respect.) Bob had told Pete that Manolo had very recently nursed his own father back to health, a statement that is at odds with his excuse after sending an elaborate deli platter after Roger’s mother died (“I was just thinking of when my father died”). He nearly lost his job but was saved by Joan (Christina Hendricks), to whom he had cozied up, bringing presents for her son Kevin and going to the beach with her.

It’s all been a calculated campaign and, in retrospect, apparent from the start. Bob was far too enthusiastic and always lurking on the periphery, offering to pay for hookers or buy toilet paper. He reeked as much of desperation as ambition. He looked to find a way to win over Pete Campbell and made a sexual advance, seeing Pete as a lonely person in need of attention. Bob may appear to be a tragic figure in some respects but also a canny one, a man possibly destined for great things simply by strength of determination. He wasn’t born into the world but grabbed it with both hands.

Unrelated but worth mentioning: the truly wonderful scene between Sally and Betty (January Jones) when they drive off after Sally’s interview at the boarding school. Attempting to reach out to her daughter, Betty has Sally light a cigarette for her and then offers the teenage girl one of her own (“I’d rather have you do it in front of me than behind my back”). Their unexpectedly easy rapport here points toward an enormous breakthrough, their shared cigarettes a symbol of unexpected unity and femininity, as Betty asks for details of Sally’s visit. Betty smiles so rarely on Mad Men that when she does it holds special importance, akin to a sphinx letting her guard down. But conversely, Sally and Don’s relationship has never been more fraught. When asked if Don has given her a beer in the past, Sally replies cryptically, “My father has never given me anything.”

It’s worth noting, of course, that while Don has given Sally many things, his real name—his true identity—is not one of them.