The night before I headed off to journalism grad school, I stayed up packing and waiting for my girl Mary on 1 a.m. reruns. Mary was Mary Richards, the television news producer played by Mary Tyler Moore in the 1970s comedy series that bore her name. Mary had dark hair, a toothy smile, an inclination toward earnest goofiness and giant hopes of winning in a male-dominated world — all traits I shared. Girls like me grew up on Mary, laughing with her and her brassy best friend, Rhoda, as they navigated their lives as single women with workmates who were also friends.

As I folded my hopes into my suitcase, the theme sang out, “You’re gonna make it after all,” and there, miraculously, appeared the final episode of the series. I hadn’t ordered this on Hulu. This was 1980, when Hulu sounded like something you did in a grass skirt. No, this was kismet — a cosmic fluke that Mary’s last show would rerun on my last night home. I took it as a sign. Had there been Twitter, I’d surely have tweeted that I was gonna make it after all, too.

Taking a leisurely look at the characters and the people behind the scenes of one of the most successful television series ever, Armstrong’s book pleases on several levels. There’s the story of simply getting the show on the air. “MTM” broke ground with its focus on the social and work life of a single career woman. The series began in 1970 as 30-year-old Mary relocated to Minneapolis after being jilted by her fiance. The producers originally wanted her to be divorced, but network research showed that viewers wouldn’t tolerate that storyline.

The first quarter of the book takes us through launching the pilot episode, in which Mary is interviewed for an associate producer job by curmudgeonly Lou Grant. “You’ve got spunk,” he famously told her. “I hate spunk.” (Confession: Not long after grad school, I worked at “The MacNeil/Lehrer NewsHour” in New York. When I found out that one of the managers was named Lew, I was so tickled to be in a parallel Mary universe that I had to restrain myself from running into Columbus Circle to throw my beret into the air — an homage to Mary for which “MTM” fans need no explanation.)

Mary was surrounded by a stellar cast, including Ed Asner as Lou; Valerie Harper as wise-cracking Rhoda Morgenstern; Gavin MacLeod as Murray, the married newswriter who’d always have a crush on Mary; and Ted Knight as Ted Baxter, the vain and dimwitted local news anchor. Early reviews called the show “a disaster.” But the smart, character-driven humor won over the nation, and the same media outlet that initially called Mary “unmarried and getting a little desperate about it” described her a few years later as “thirty-three, unmarried, and unworried — Mary is the liberated woman’s ideal.”