(FORTUNE Magazine) – Best friend lost his job. Dad's savings are toast. War and smallpox on your mind. Tough times all around, eh? It could be worse. Suppose you had to capture all that angst and agita and transform it into words that reassure and inspire with their sincerity and aptness? Keep it under 20 words. And skip the rhyming poetry--that stuff just doesn't sell anymore.

Yes, you could have one of the most challenging assignments in business: writing greeting cards appropriate to this era of stress. Turning the crummy zeitgeist into a four-by seven-inch sunbeam with a postage stamp is tough but necessary: The fastest-growing variety of card today is the "encouragement card."

"Be brave, dear friend. You're stronger than you think," goes the line on a card with Winnie-the-Pooh characters struggling in a storm. "Who cares?" shouts another card, with the encouraging "I do!" inside. There's even a scold for your chronically depressed chums: a daisy with a big smile, above the words "Hey, remember this face?" Inside: "Start wearing it again, will ya?!"

Some encouragement cards are wordy and heartfelt--the kind of stuff your grandmother might send her sister. "Even in times of darkness, a seed is stirring, reaching beyond the ground toward the light. Still unseen but on the way are lovely blossoms and new growth. The season is not yet here, and the waiting is long and hard, but believe and it will come." Others are brief. A photo of some lemons opens onto a brisk "Well, that sucks!"

Devising an encouraging card is harder than it looks, say the people who write them, and it takes more than kittens and corn syrup to make one. "Before I began, I used to laugh at this kind of work," says Nicole Fraser, a card writer for American Greetings in Cleveland for the past 15 years. "I've come to regard it as a humble but noble genre." One of her cards shows a piece of fruit whizzing through the air. "Who gives a flying fig?" asks the caption. "I do," answers the inside.

Where, you may ask, are the references to unemployment, deflated 401(k) plans, or anthrax? As tough and gritty as you think you are, a lot of tact is employed to make sure the card you get doesn't backfire, especially when you're already feeling a tad, um, unsettled.

"The first rule of writing encouragement cards is, Don't name the distress," says Marita Wesely-Clough, head of demographic research for Hallmark, based in Kansas City, Mo. These cards are for the giver to extend sentiments of support and well-wishing, not to help the recipient relive the thrill of seeing a pink slip in the pay envelope. There are no "Too bad you lost your job" cards, and the card you send someone still rattled by Sept. 11 won't have a picture of burning Twin Towers on it. (At least not from Hallmark and American Greetings, which together account for about 90% of all cards sold. "E-cards," however, designed to be sent on the web, tend to be uninhibited. One of them says, "Roses are red. Violets are blue. Al Gore's out of work. And so are you.")

So what's the secret of good card writing for bad times? The writers insist that despite some rules, there are no glib formulas. "The card should sound like a personal letter and feel like it's between you and me--like I wrote it for you," says Wesely-Clough. Fraser concurs: "The card has to feel personal but suitable for 250,000 people to buy." The words may have a certain cadence, but rhyming couplets and singsong poetry are rare. Often the cards praise the recipient's pluck and courage in the face of adversity. Hallmark card No. 70000-11854 shows a lone flower in a bottle with the words "You've been through so much lately, and I know it has taken a lot out of you ... But I know that you'll handle it, because you're one of the bravest people I've ever known. You might not see yourself that way, but I do ..." Inside, the card assures the reader that "I'm here." An American Greetings card (99NCH 4065-03M) shows a snowy, intimidating mountain and declares, "When the going seems all uphill ... just think of the view from the top. You're doing great."

Even before Sept. 11, "we had spotted a new thing on the horizon," says Hallmark's Wesely-Clough. "We called it peace of mind.... A recognition that things don't last, but relationships do."

There is no giant cardboard thermometer in the writing room at Hallmark or American Greetings that illustrates the current state of the zeitgeist, nor a list of delicate topics that must be addressed. The writers are expected to get out and mingle, and sometimes even urged to see a particular popular movie to gauge the proper tone. Fraser, the mother of two boys, helps coach their basketball teams. Hanging out with the other coaches, most of them male, helps her understand what men are thinking and what kind of language resonates with them.

A changing zeitgeist, like a bad economy and the threat of terrorism or war, will be reflected in the tone of a wide variety of cards, notes John Peterson, a writer at Hallmark. "I had to write a birthday card for a father to give to a daughter," he says. "The editors introduced the idea that things are a little shaky." So instead of a card with wildflowers and ponies, Peterson produced one that says, "When I see how complicated the world is, I take comfort that there are strong people like you." Writers know when they get it right, says Rachel Bolton, a Hallmark spokeswoman. "They read the cards to each other. There's an aha! that runs through the room."

Of course, if all that sincerity and tenderness make you squirm, there's always an alternative approach to bucking up your buddies: gruff or silly humor without a hint of feeling. One of Hallmark's most popular writers, Oliver Christianson, writes only funny cartoons. Nothing topical, political, or economic. "A little humor will help more people than duct tape ever will," says Christianson, whose nom de plume, Revilo, is his given name spelled backward. One of his favorite cards shows a rooster sitting at a bar. The bartender is handing him a drink, with the words "This is from the fox down at the end of the bar."

But even card companies far more edgy than Hallmark or American Greetings can't ignore current events and changing sensibilities. Ron Kanfi, president of Nobleworks, a small card publisher in Hoboken, N.J., that prides itself on trampling the boundaries of good taste (its butch-looking Mother Teresa on a motorcycle is popular), had to yank some cards after the World Trade Center attack. "We had a cartoon of a pilot relaxing on a beach, using a walkie-talkie to contact a plane flying overhead. It said, 'Ladies and gentlemen, this is your captain speaking....' We couldn't use that. We do risque, but not dark. Dark is not a hit these days."