Because they and their children haven't seen each other since morning, evenings begin decibel-high at Tiana and John Leonard's townhouse in Manhattan's East 70s. Andrew, aged 12, chess player and science award winner, machine-guns his newest facts and latest experiments. Amy, 8, pops the head off a Barbie doll and solemnly observes to a visitor: "As a couple, I would say of my parents, since they've been married for 15 years, they will never get a divorce." She then asks Mommy if she can go to the movies barefoot. "No!"

Eventually, quiet descends and the parents reunite over a drink. "We don't see each other enough to fight," says Tiana. "And besides, John doesn't like to."

At 35, John Leonard is editor of the New York Times Book Review, the most influential publication of its kind in the country. Benigna Christiana Morison Leonard, 36, has her own career at Rockefeller University where she is Dr. Leonard, a physiological psychologist and assistant professor. In September, she moves to Mount Sinai Medical Center on a three-year grant from the National Institutes of Health to "try to figure out what parts of the brain control behavior of very young animals."

"If I didn't have a career and a husband as successful as John I'd be a psychotic or a suicide," says Tiana.

"Well, which is it?" John wants to know.

"Both, probably." she replies.

Dinner is prepared by their Haitian housekeeper, and then the evening work begins. She curls up in front of the television set with a scientific journal, ignoring the tube. He scans his latest books and the screen—sometimes flipping back and forth among three programs. John must keep an eye on TV as Cyclops, the bristly and witty television critic for the Sunday Times Arts and Leisure section.

Early in the morning before he goes to the office, John writes his novels. The one in progress is a mystery. It will be his sixth book, four of which have been published. None has made the Times best-seller list, though Black Conceit, about an idealist's disappointment in the imperfectibility of human nature, was nominated for this year's National Book Awards. It didn't win. "I was pleased, but I didn't belong in that company," says John. "I'm not a good novelist. It'll take me another 15 years to write a good novel."

John Leonard was born in Washington, D.C. where his mother was a secretary in Roosevelt's White House. After his parents separated, she supported John and a younger brother by writing newspaper lovelorn columns. When he was 8, they moved to Long Beach, Calif., and at 17, he headed back east for what was supposed to be a Harvard education—only to flunk out.

Though he couldn't seem to study, John had no trouble at all writing for Harvard's daily Crimson. The night editor was a Radcliffe junior, Tiana. "I had already gone through all the other men on the Crimson when I met John," she says. "He just hung around the night desk, this invisible sophomore. I asked him out on our first three dates."

On the third evening, they walked to the top of the statehouse in Boston, forced open a window and climbed onto the catwalk around the dome. "Standing there, looking out over Boston, I thought, he's for me."

That summer she took him home to meet her family at their 1,100-acre estate in Peterborough, N.H., a "feudal barony," he calls it, which for five generations has produced Morison scholars, statesmen, scientists and writers (including historian Samuel Eliot Morison). John felt an immediate liking for Tiana's father, a Harvard-trained M.D. who now teaches at Cornell, and her dynamic Russian-born mother. The Morisons just as quickly adopted him, and he has written their family history into his novels.

When Tiana graduated, they got married and moved to California, where it was John's turn to finish college—at Berkeley—and she went on to her masters. "I found six months after I married John that the only thing I could do for him was talk to him," she says. "He wasn't interested in food, or whether there were flowers on the table."

When they moved back to Boston, Tiana transferred to MIT and John wrote, often about the turbulent ideological conflicts of the '60s. In 1967 Leonard was hired by the Times as one of the "previewers" who recommend books to the Times' critics. Within three years he was tapped to take over the Sunday Book Review section.

If they chose, the Leonards could go to some kind of literary party seven nights a week. But unless they can go as plain guests and not to adorn the affair for publicity, they decline. When they themselves entertain, it's usually informal: 40 or 50 for a buffet of rice, beans, salad and ham. Once in a while there are sit-down dinners for eight, a careful mix of scientists and writers. And on Saturdays there is dinner just for two.

The pattern is unvarying. So is the menu. The children are tucked into bed. Then Tiana puts on a long skirt, John a tie. There are martinis and roast beef and candlelight...and M*A*S*H and Mary Tyler Moore. During All in the Family, they eat. "Because it's a wretched program," he says. "And if you want to know more, you'll just have to read about it in my book This Pen for Hire."