Bo and candy. Bo and John and candy. And lies, Bo not telling lies to John about candy . . . the whole movie crew seems to know the routine here in Williamstown, Mass. They're shooting "A Change of Season," which is Bo Derek's second movie -- she being the perfect "10" on a scale of one-to, in the movie of the same name.

So it's just a joke when somebody walks into the Victorian living room where her husband John Derek, 53, is lying in front of a wood stove, and says:

"Bo didn't have a candy bar."

But Derek mishears. "She did?" he says in his analgesic baritone. "Bo?"

Bo is sitting at the dining room table. She looks up. She looks scared.

"No, she didn't," the guy says to Derek.

But courage mounts in Bo's face.

"Yes, I did!" she announces. "One of those little ones."

"If you eat four or five of them, Bo . . ." Derek warns. He doesn't have to say more.She knows. Derek has just finished telling someone that "Bo used to lie about her food but I don't think she lies anymore." He has also explained: "If she's eating and pretending she isn't, she's lying and she loses her nobility, she can't look people in the eye. I can see it in her eyes."

"I ate one! I don't care!"

"Bo," says the analgesic baritone.

"It was good, too!"

"Bo."

"Anthony gave it to me, and then he had one, too!" she says, referring to her co-star, Anthony Hopkins.

"Two wrongs don't make a right, Bo," Derek says, in a tone of voice as creamy gray as his bomber jacket, a tone which always seems to be saying "Of course . . . of course . . ."

Bo gets up and walks outside to shoot a scene. Derek lingers in front of the stove, the pretty-boy star of the early '50s iron-haired now. If the bone structure required for youthful beauty seems a little too sharp now behind his blue sunglasses, he retains his predatory languor. And why not? He's been married to three famously beautiful women, especially Ursula Andress and Bo, with Linda Evans, star of TV's "The Big Valley," in between. He photographed them all nude for spreads in Playboy, too. They looked, to the rest of the world at least, like trophies, prize kills.

Has he talked to all of them like this?

Of course.

Didn't any of them ever throw a vase?

"If they throw a vase, I'll throw it right back," he says, with a sparkle of astonishment. "I can't tolerate it. I'm only being honest. I only want them to be more beautiful. It's my nature.If they don't like it, they can take a hike. I never pushed any of them into their careers. Ursula, Linda and Bo were all passively pursued by the movies. I only suggested they do a better job of it."

Of course . . . of course . . . the creamy bariton . . .

John Derek met Bo when she was 16, and he was casting a movie he shot in the Aegean, on Mykonos. He was married, at the time, to Linda Evans.

"I had everything I wanted in Linda, so why I became interested in Bo I don't know. At that time she couldn't hold a candle to Linda, but something about her got me involved. She's an interesting girl, Bo is."

Bo had been Mary Cathleen Collins, the daughter of a motorcycle dealer and a movie-biz hairdresser in Torrance, Calif. Derek left Evans for her ("I never sneaked around on her, I was always honest") and renamed her Bo. He remains, he says, on good terms with both Ursula and Linda. ("Tell Linda to get off her duff and tell you good things about me.") A first wife, Patricia Behr, has remarried and "there's no love lost between us," Derek says.

Anyhow, he took Bo to Germany from Greece: "In the United States you have statutory rape and the Mann Act to contend with." It was Linda Evans who researched the legal situation before Bo and John returned to be married.

They've been together for six years. She had a small part in "Orca, the Killer Whale," and then "10." The Mykonos movie was never released. Neither was a hard-core poronographic film called "Love You" they made together in Hawaii -- they produced, and did not perform. At 23, Bo is the hottest thing in business since Farrah Fawcett, with reputed million-dollar movie offers coming in.

Her acting is so far untested. "She's not an acrtess, she's a picture personality," Derek says. In "10" she was the paradigm of the burgeoning, firmly pneumatic, beach-bouncing, surf-sighing, vapid beauty and is now the star of a poster being sold nationwide.

She is the ultimate fantasy in both poster and movie, in which she is the object of Dudley Moore's middle-aged lust -- a lust which verges on consummation to the tune of Ravel's "Bolero" in an Acapulco hotel room. Then Moore discovers that what's important is love, not perfect physique, and viewers are left sadder but wiser. And truly startled by the presence of Bo Derek.

Each step in her short career has been watched over by Derek, who first learned the business from a director father and an actress mother. He acted in 19 movies, making his first hit with "Knock on Any Door," with Humphrey Bogart, and going on to swashbuckling roles, along with "Exodus" and "The Ten Commandments."

"I never took that s--- seriously," he says.

The baritone drones on an on. Derek keeps talking in a syntax studded with the scatological. But then, as he says, "most of the world looks like . . ." a particular part of God's anatomy, as it happens, and "the world is based on lying," but he's used to ti, of course, he understands and Bo doesn't, of course.

Everybody lies; it's the name of the game. So Bo and I have our own little world. The only three people in the world I trust are Ursula, Linda and Bo. They learned not to lie to me. I'll belabor a point for hours to prove somebody is lying. And if I've got the actual proof, I won't tell you, I won't give you my ace hand. I'll find out how far you'll lie. And finally if you admit you're lying, admitting it doesn't get you off. Because that may just be the tip of the iceberg.

"Love and honesty, that's all that's decent in the world. Then it's up for grabs." And honesty is beauty, and when Bo eats too much she loses her beauty, fat "covers her face," Derek says, and besides, he doesn't want her lying about it.

The motel suite is strangely messy for a couple so devoted to beauty and perfection: clothing in the chairs, a scatter of weights for the barbells, a box of crackers, a bottle of champagne. John and Bo lie on beds they've pushed together.

"Love and beauty and honesty are the most important things -- that's all there is," Bo says. "Everything he's taught me has been pro-me. There's such a difference between what I am now and what I was before."

What was she before?

She doesn't like this. She is nervous. She keeps turning the dial on the phone, letting it whirl back, turning it. . . .

"Things before weren't much of anything," she says.

In diffused light, with no shadows, Bo's face verges on round -- cold and lovely, but round. But given a certain slant of light, the cheekbones rise, the nose thins, the eyes shine blue and she is a world-class beauty.

Derek hates any photographer who shows less than that, "these goddam paparazzi who lie down in front of her and shoot up at some crappy angle -- this is one f------ beautiful lady and they want to show her ugly. We're bringing out a book of pictures of her and that will settle this s--- once and for all. I'm taking the pictures."

Anyhow, Bo twists and dials on the bed, looking either petulant or sad or ill-at-ease, it's hard to tell.

"I never get mad at him. That would only be like getting angry at myself," she says.

"I get mad," Derek says. "I get mad. I get frustrated. It's like being with a prize filly, and you want to ride it, not just train it."

Is the training complete?

"I'd like to let her swashbuckle a little," Derek says."Yeah, I'm not gentle, I get angry. And many times I'm wrong."

"But you're the first to apologize, John," Bo says in her sad, intriguing husk of a voice.

"I don't forgive easily," John says. "If a filly kicks you and then says she's not going to kick you anymore, you say: 'You kicked yesterday.' Don't you?"

Then Derek is asked about the paparazzi, and his extraordinary jealousy of other photographers. It is suggested that a man who photographs his wife nude for Playboy is in a strange position to be demanding privacy.

"What? Are you actually saying that? My God, the puritanical a------- in this country. How did God make her! How? With clothes on?"

This leads Derek to the press, and how it's mostly bull, lies, filth, the whole world is like this, they don't need to attack Bo, they attack him -- in the '50s, before he quit his movie career it was "this prettyboy s---" and now "they've got to find a fly in this magnificence. Talk about cynicism. I should be so cynical, I should drop-kick the phone across the room everytime one of these f------ calls."

And he concludes: "I've never met anybody as bluntly honest as I am."

Hasn't anybody ever been honest?

"Who's been honest, John? Bo asks.

"Nobody," Derek says.

Bo shows him a letter from a magazine whose reporter is here in Williamstown. The reporter is asking Derek for slides of Bo. Derek rages that the magazine already sent a photographer onto the set. (Earlier that day, Derek had accused the same photographer of not being from that magazine.)

"you sit there and listen to this," Derek snaps to a visitor. This magazine, he says, "they're supposed to be factual. I'm going to call them with you sitting right here . . ."

He calls. The tirade continues with violent obscenities on the phone as John threatens to put Bo on Barbara Walters and have her "exposed" this magazine.

Bo, meanwhile, gets up from the bed and puts on a long goosedown coat. She stands in the middle of the floor and listens to this litany of accusation. She stares at the floor. She waits. She sighs. She blinks. She sighs. She leaves. Derek pays no attention.

He is still choleric at the end of the call. He accuses the visitor of spending all his time with Bo, not him. He shouts: "You're going to say I'm paranoid."

He cools down enough to provide assurance that he was once "the fastest gun in the world." And an expert in knife-throwing, hatchet throwing, parachuting. He says that never has a star rocketed to the top as fast as Bo.

He is sure no one else could handle Bo as well as he has: "I have a vested interested. I love her." And: "A woman becomes my whole life."

It gets confusing: "The illusion of Bo should have nothing to do with the real one, or it'll destroy the real one." Yet his photographs, he says, show "the real girl."

"I truly believe I'm much more sensitive and respectful of a woman than most men are. I've had six years to abuse and exploit her and I haven't."

Bo calls, at one point. Derek says: "Not right now, baby. In a minute.

I'm being interviewed. Don't worry."

Then he tells the story of the photography session. He's already told it once today, but he tells it as if it explains everything about their relationship.

"The other day we drove out in the country to shoot stills. We found a covered bridge and we all got out -- it was Anthony, Bo and Michael [Brandon, a co-star]. I shot a lot of stuff. On the way back, Michael said: 'Wow, did I get a lesson today.' He said: 'The way you work together -- you tell her to go over there and she goes. And she makes a photograph.

"The sun would go behind the clouds and she'd move, automatically to catch the light," Derek says. "She knows exactly which way to turn her fingernails when I'm taking pictures of her. She finds light. Without light on earth there is nothing. She lets God light her."