There’s a secret reason there’s a big wooden “L” on top of the bookshelf near my desk.

Obviously, it represents my first name. But when I saw it at Target a few years ago, I was immediately transported back to my adolescence.

Mary Richards, the lead character in “The Mary Tyler Moore Show” (1970-1977), had a big “M” on the wall of her enviable Minneapolis apartment. I adored the show and wanted my own letter, not to mention a cute and extensive wardrobe, a flat with French windows leading to a balcony and a job as an assistant producer of a TV news show.

I was 14. A girl’s got to dream.

Now, thanks to the miracles of modern media, I am binge-watching Mary Tyler Moore. I’m both reliving my past and conducting anthropological and archeological studies.

My husband, Paul, and I like to, as we put it, “have a sitcom going.” It seems healthy to laugh regularly. One of our recent selections was “MASH.” Though I’d watched that show as a kid, it did not prepare me for the jolt of recognition I got from the very first episode of Mary Tyler Moore. Mary’s apartment included a record player, a tiny portable TV and a push-button telephone. Oh, the horrors of not getting to the phone on time when it was ringing. We didn’t even have home answering machines in those days.

Mary’s outfits — lots of patterns, bright colors and miniskirts — were designer versions of what my friends and I wore at the time. I had recently been working on some fiction set around 1970, and had been looking online at period sewing patterns. Mary Richards, of course, had “the look” of 1970. She was a clothes horse.

In season two, though, Mary no longer wore miniskirts. They were still in style and other characters wore them, but she adopted a more professional look of suits and dresses. Suddenly, I found myself in the role of amateur anthropologist. What was going on here?

When the show begins, Mary has come to the big city (cue the iconic theme song) after a romantic breakup. She seems to have a secretarial background, and while her new position as assistant producer sounds important, she’s still typing (on a manual machine).

Mary and her upstairs neighbor, Rhoda Morgenstern, lament the fact that they are 30 and unmarried. Life is passing them by. Marriage had been a life goal for them.

But then Mary gets a proposal — and turns it down. She asks her boss, Lou Grant, for more challenging assignments. A corner has been turned; Mary is more satisfied with her life as a “career woman.”

And as time goes on, super-nice Mary, who has a hard time saying no or setting boundaries, gets ever more assertive.

This evolution got me thinking. I would have been 16 years younger than Mary and Rhoda — almost a generation. I grew up thinking I’d want to get married after I graduated college. Most of my friends were college-bound. I remember wondering why a pal who was in the top 10 of our class was going to nursing school. Why didn’t she want to be a doctor?

I know that sounds judgmental, but it proves my point: The fictional character of Mary Richards was reflecting some major changes in society. The show reaffirmed my sense of independence.

The women’s liberation movement, which had started in the early 1960s, was still well underway in the early ’70s. The men of the WJM-TV newsroom could be sexist, particularly the oafish anchor Ted Baxter. (Once, while introducing Mary on the air, he refers to her attractive legs.) When Mary has to fire the sportscaster, she invites him to lunch and he starts pawing at her.

It was still the bad old days. When I was in college, I attended an extracurricular “assertiveness training” class, so I, too, could learn to say no.

While I’ve been rediscovering the cultural mores of the 1970s, I have been digging into the artifacts. What a colorful era it was. Orange was big. In season three, Paul and I fell into a routine of noting when the characters were wearing orange, and it seemed somebody was in every episode. An orange pantsuit is a sight to behold, believe me.

In season four, there seemed initially to be a change to yellow. Were the ubiquitous “harvest gold” kitchen appliances about to burst onto the scene? But orange hadn’t completely gone out of style, it turns out. Some characters were still in minis, and Mary wore pantsuits to work sometimes. (This after an earlier episode in which Lou says he doesn’t want to see a woman in slacks in the office.)

I don’t think I could define the 2020s by using a color palette, and there certainly is no uniformity in dress. We’re a fractured nation, in more ways than one. It is hard sometimes to find a single friend who has watched the same show as you, even if it is a big hit on Netflix.

Is it possible to have too many options? It can be confusing, especially for young people. But then I watch an episode of “The Mary Tyler Moore Show” and remember being 14, when I saw the possibilities were endless.

Which is why, whenever I glimpse my big wooden “L,” I smile.

Liz Soares welcomes email at lizzie621@icloud.com.