We’re likely to get a few answers, but not as many as we might like. As any devoted “Mad Men” fan will tell you, the many nagging questions only add to the pleasure of watching the show. Key dramatic developments often happen off screen, especially in the long break between seasons (hello, Sal got married?), and expository dialogue is rare. Instead, we're expected to piece it all together using our wits and imagination. As a TV viewer, being treated like an adult is mostly a delight, but it can be confusing sometimes.

“Mad Men” returns to AMC on July 25th, and seemingly the whole world—including President Obama —is eagerly waiting to see how last season's many cliffhangers will be resolved: Will Betty marry Henry Francis? Will Sterling Cooper Draper Pryce succeed? Will we ever see Paul Kinsey and Ken Cosgrove again?

10. Has Glen Bishop gotten over Betty?

Remember Betty’s bizarre friendship with Glen, the maladjusted son of sexy divorcee Helen Bishop? Yep, it was weird. Glen (who, incidentally, was played by Matthew Weiner’s son, Martin) watches Betty while she goes to the bathroom, and she later gives him a lock of her hair. Helen isn’t amused by the flirtation, and confronts Betty about it at the grocery store; Betty impulsively slaps her in retaliation. Glen went "underground" for a season, until the end of Season 2, when he briefly turned up in Sally's playhouse; there's been no sign of him since. The relationship, I think, was meant to show how emotionally stunted, lonely and starved for male attention Betty is, and it worked in that regard—the whole “affair” was thoroughly disturbing. Is Glen still pining after Betty, or is he crushing on other alienated housewives?

9. What about Arthur, the equestrian with the wandering eye?

Glen wasn’t the only male to harbor a doomed crush on Betty Draper. In Season 2, Betty meets Arthur, a flirtatious young equestrian. Rather than having an affair herself, Betty orchestrates one between Arthur and her friend, Sara Beth. It’s a nakedly vindictive move by Betty, who’s miserable about Don’s philandering and wants to see someone else suffer. In "The Mountain King," Sara Beth calls Betty to say she’s made a “terrible mistake” with Arthur, and she's devastated that he'll be getting married that weekend. That's the last we hear from Sara Beth, so we can only speculate as to how destructive the affair turned out to be.

8. Why didn't Greg become chief resident?

Joan’s lifelong ambition of marrying a handsome surgeon was derailed last season when her husband, Greg, lost out on a residency at St. Luke’s Hospital. The reasons, though, are murky. At a dinner party at Joan’s house, the guests discuss an undisclosed mishap involving a pneumonectomy (that's a lung removal, in case you were wondering). “It’s a complicated operation. Everyone gets bad results once in a while,” says one of Greg’s fellow doctors, by way of encouragement. Joan is shocked to hear about it, and her surprise only adds to the excruciating humiliation of their relationship. We never find out just what happened in the ill-fated operation, or even if this incident is what ultimately doomed Greg's career as a surgeon, though presumably he doesn't have the deft hands the job requires. On the plus side, we did get to see Joan play the accordion.

One of the weirder moments on “Mad Men” came at the end of Season 2 when Don, in self-imposed exile in California, temporarily took up with a group of mysterious aristocrats in Palm Springs. Don is seduced by 21-year-old Joy, who enjoys an especially close relationship with her father, Willy, a vicomte with a French-sounding accent. The encounter helps Don realize he’s not cut out for their free-loving lifestyle, but that’s just about all any of us learn about these fabulous nomads. Seriously: What was their deal?

6. Was baby Gene switched at birth?

A friend recently alerted me to the (admittedly far-fetched) possibility that little Gene might not be the Drapers’ baby--as if he didn’t already have enough problems on his hands. OK, so this is technically a conspiracy theory and not an unsolved mystery, but consider the evidence: In the supremely trippy episode “The Fog,” a drugged-up Betty has hallucinatory dreams about her parents. “Be happy with what you have,” her father tells her. Betty eventually comes to with a baby in her arms, but is confused to discover that Gene is a boy, not a girl. Later, when Don returns to the hospital to pick Betty up, he walks past Dennis, the prison guard with whom he’d bonded in the waiting room. He’s wheeling his wife—but no baby—out of the hospital, and when Don greets him with a friendly smile, Dennis looks away, abashed. Maybe he’s embarrassed about getting mushy in front of Don or maybe he’s feeling guilty for switching babies? Yes, it’s a stretch, and no, I'm not quite convinced, but if true, it wouldn’t be the first time the show has employed plot lines worthy of “Days of Our Lives." Plus wouldn't it be appropriate for Don--who changed his own identity--to end up with the wrong child?

5. Did Sal go cruising after getting fired from Sterling Cooper?

Poor Sal. When last seen, the newly unemployed art director was calling his wife, Kitty, from a phone booth in a cruising spot somewhere in New York City. Surrounded by cartoonishly gay, leather-clad men, Sal told Kitty a predicable story about working late, hung up the phone, and nervously walked out of the booth. But did he walk out of the closet, too? We can probably assume that Sal went on to pick up one of these leather-bound dudes, and that the frustration of losing his job is what finally forced him to act on his sexuality. But what’s more intriguing is the possibility of what happened after that—did Sal break it off with Kitty, or go on to lead a double life, as so many gay men did in his day? His journey would have been so fascinating to watch, which is why his absence from the show is so heartbreaking. Call me a hopeless optimist, but I’m still rooting for his return.



4. What happened to Duck Phillips’ dog, Chauncey?

Recovering alcoholic and divorcee Duck Phillips is one of the more pathetic characters on “Mad Men.” Of course, there was the time he turned off the TV so he could get it on with Peggy before she found out about JFK’s death. But his lowest moment? In Season 2, Duck’s ex-wife shows up and asks him to take back their Irish Setter, Chauncey; she’s remarrying and her new husband is allergic. Rather than keeping the dog, Duck sets him loose outside the Sterling Cooper offices at 405 Madison Ave; Chauncey was never seen again. It was possibly the single cruelest act ever perpetrated on “Mad Men,” and that’s saying something.

3. Did Paul Kinsey dump Joan?

I know, it’s hard to believe anyone could dump Joan, but the evidence strongly suggests that everyone’s favorite office manager was once scorned by schlumpy copywriter, Paul Kinsey. From the very first episode of “Mad Men,” when Joan jokes that Kinsey was a “mistake ” she’d made in the past, it’s clear that the two once had something; unfortunately, the precise nature of that “something” is much more difficult to discern. They certainly strike me as an unlikely pair. Kinsey’s too much of a dilettante for the sexy and savvy Joan, but then again, she dated him before the beard and the mohair sweaters. So what drove these two apart? Let’s piece together the scraps of evidence. In “Nixon vs. Kennedy,” Kinsey asks Joan, seemingly out of the blue, "What did I do wrong?" Presumably, he's referring to their break-up. “You’ve got a big mouth,” she answers. Early in Season 2, Joan tells Kinsey’s new girlfriend, who is black, "The last thing I would have taken him for is open-minded.” Kinsey accuses her of being jealous. Odd couple or not, these two are still mad at each other about something. What could it be?

2. What happened to Peggy’s baby?

Peggy is the one character who can almost match Don in terms of inscrutability. Take, for instance, the numerous mysteries surrounding her baby. All we really know is that she went into labor the same day she was promoted to copywriter, had a baby, and spent a considerable amount of time in the hospital. Beyond that, we’re in the dark. Indeed, it seems like the writers intentionally want to throw us off the scent. Peggy’s sister, Anita, also had a baby shortly after Peggy (astute viewers will remember that she was pregnant in the flashback scene at St. Mary’s). In an episode from Season 2, Peggy pays a visit to her family and on her way out, peeks in at an infant; presumably, this is Anita’s baby, though we’re led to believe it might be hers. In the Season 2 finale, Peggy tells Pete she gave the baby up. Does this mean she gave it up for adoption, or just that her sister is now caring for it? It’s also unclear whether Peggy gave up the baby voluntarily—because, as she tells Pete, she “wanted other things”—or if the state intervened after she had a breakdown, as Anita has implied. Season 3 brought precious little news in this category: Pete still hates Peggy, but that's all we got. Whatever happened, Peggy seems to have taken Don’s advice and tried to forget the whole episode completely. The same can’t be said for us fans.

1. What was Don Draper doing all those years?

Don Draper and Jesus have at least one thing in common: no one’s quite sure what they were doing before the age of 30. Over the last three seasons, the truth about Don’s past life has slowly emerged, but there are still long chapters missing from his biography. How, for instance, did Don go from selling cars to working in advertising? At one point, Roger says he “discovered” Don in his old job, but that’s all we know. Let's do the math: Dick Whitman “became” Don during the Korean War, which started in 1950. Don married Betty in 1953, after meeting her when he was writing copy for a fur advertisement. That means that Don went from car salesman to ace ad exec in less than three years. That’s a pretty meteoric rise, wouldn't you say? We also know almost nothing about what Dick/Don did as a young adult--before he went to Korea (according to my math, he would have been at least 24 at the time). I’m hoping Season 4 will tell us more about Don's mysterious past. Another lingering Don-related mystery: Who told Bobbie Barrett about his prowess in bed?

Do you have theories about any of these "Mad Men" mysteries? Nagging questions of your own? Please share in the comments!

--Meredith Blake

Photo: Don Draper, international man of mystery.

Credit: AMC/Carin Baer