On this day devoted to demonstrations of affection, this too-brief moment of rampant sweetness, no one is so uncelebrated yet so indispensable as the professional greeting-card writer. What manner of person is it who can place herself, for example, in the role of a child to compose these lines:

I may not know big words

Like on a grown-up valentine,

But what I'd really like to say is,

"Please, won't you be mine?"

That's one of 2,000 different Valentine's Day messages available this year from Hallmark Cards, a corporation that brings in $2.5 billion annually with its "social expression products."

The Hallmark folks expect 1 billion valentines to be exchanged this year, up from 900 million last year. Only Christmas generates more action, they say. (Hallmark, based in Kansas City, Mo., has about 45 percent of the total greeting-card market.)

Behind those big numbers are human beings -- more than 50 of them in Hallmark's case -- sitting at computer terminals within workstation cubicles and writing. Writing a lot.

The preceding verse is by Mary Miro, 50, of Overland Park, Kan. She also wrote this:

God gave us hearts made for caring,

and mine cares for you!

Happy Valentine's Day

"I think being sensitive to what a person would want to hear when they're getting a valentine is very important," says Miro, who has been on Hallmark's writing staff since 1984. "I do a lot of putting myself in other people's places. And I have to confess, I am a romantic at heart. And I think that helps."

Miro, a divorced mother of a teenage son and daughter, has earned undergraduate degrees in biology and elementary education. She had a temporary job in a research lab ("doing cell cultures for a pharmaceutical company") when she saw an ad in a St. Louis newspaper that changed her life. Hallmark was looking for writers.

"I had always written for friends and just for {myself}, sort of like a hobby," Miro says. "Verse and other things. Short stories." She sent samples of her stuff, then completed some Hallmark writing exercises. "They might ask you to write an eight-line verse on love, or maybe a Halloween card for a child, something like that." She got hired.

Although humorous cards are a fast-growing segment of the industry -- they make up about a quarter of the valentine market -- most people still buy what's called the "traditional sentimental" card. And that's the kind Mary Miro writes best. "I think probably my strong points are in verse and conversational-type messages that are really heartfelt," she says.

Son, we love you.

We feel very lucky

to have a son like you,

a son who has grown into a unique,

wonderful person.

And on Valentine's Day,

we just wanted

to let you know

how much you mean to us.

There are about 25 writers in Miro's department, almost all of them women. (The joke writers have their own space. Most of them are guys.) They spend their whole day writing. Apparently, not much time is wasted wrestling with the muse. For a Hallmark writer, "an ideal number of accepted messages might be 30 or 35 per month," Miro says. "But we turn in a lot more than that." Maybe three times more. "Not every idea that we turn in is as wonderful as we think it is when we write it," she says with a chuckle.

At such a pace "you don't get too attached to your work," she acknowledges. "There might be a few that, if you see them, you say, 'Oh yes, I remember writing that and how good it felt.' "

Still, Miro takes great satisfaction in the job. "Even though you may not see the person who's getting a card," she says, "you know that you're touching someone out there, and helping people to express something maybe in a way they couldn't do it. And that's a good feeling."

Asked about her all-time favorite piece of writing, Miro says it wasn't a valentine but a children's card -- "for a child who has lost his tooth. It had a funny little rhyme in it. For some reason, I always liked that rhyme." Would she mind sharing it? "I can't remember right now exactly how it goes," she says. "Sorry about that. If you stay here enough years, you'll have thousands of things that you've written, and it's hard to remember. I'm truly serious about that. We just write a lot."

What if she happens to be in a bad mood? Even professional greeting-card writers must have their bummer days. Well, says Miro, perhaps that's the time to visit the company library and thumb through a few magazines, children's books, books of poetry. "I might go in there and research for half an hour. And that always expands your mind and gives you new ideas, and it brings you back to the topic at hand. It's nice."

Then again, "sometimes, if you have a deadline, you have to write through {a bad mood}," she says. "It's not as hard as it may sound. It really isn't. It may take a little longer than on a day when you really feel on top of the world. But we can usually manage to pull it off."

Sure wish I could see

your cute little face

and get a humongous hug, too.

But since we're so far,

I guess I'll just settle

for sending this bear hug to you!

Have a Happy Valentine's Day

The valentines reprinted here were written by Miro 18 months to two years ago. That's the time it takes for a writer to come up with a message, an editor to approve it, the art department to design a cover, and the company to print and market it. "I just finished working on some Halloween messages," Miro says.

As demanding as the work is, Miro doesn't hesitate to say: "This is where I'm going to stay. It's a wonderful place. The people that I work with are just wonderful people. It's hard to think of any other place in the world where you would have so many creative minds all under one roof.

"Every so often, I stop and think about it. And I'm kind of awed at the talent that's here, because it really is quite amazing."