It is a strangely disappointing moment. As magician Harry Blackstone Jr., son of the Great Blackstone, reaches to adjust a curtain in his hotel room, the sleeve of his jacket pulls back and for an instant the rope wrapped tightly and twice around his left forearm is visible.

First the unavoidable ah, ha! Has something up his sleeve, just like you suspected. Probably a whole hardware store within that black, double-breasted expanse. Caught him.

And then the realization you would rather not have seen the rope.

"I don't know anyone who doesn't enjoy magic," says Blackstone. "I don't know anyone who'll say, 'I don't want to see the bending of reality. I don't want to see things I don't understand.' I haven't heard that five times in my career."

So in his new book, "The Blackstone Book of Magic and Illusion," which he wrote with Charles and Regina Reynolds, Blackstone gives an abbreviated history of magic in general and his magic-entranced family in specific. He writes about what he calls the "psychology of magic," "the science of illusion" and his father's battle for fame with Harry Houdini. He includes pictures like the one he captions, "The penetration of a pretty woman by twenty-four tubular light bulbs has been a feature of the shows of Blackstone father and son." He even concludes the book with directions and diagrams of card, coin and rope tricks for the aspiring magician.

But that lady with the tubular light bulbs? Or the Great Blackstone's version of the "Levitation of the Princess Karnac"? Or the transformation of Harry Jr.'s wife, Gay, into a 450-pound Bengal tiger?

Sorry. You can't see those ropes.

"Deep in their hearts, people want to believe in magic," he writes, and provides no answers.

The book is, in part, a tribute to his father, who was born 100 years ago this year. It is a celebration of his own career; he was born 50 years ago. And it became a tribute to his son, Harry Blackstone III, a 25-year-old musician who died last August when a truck he was repairing fell off the stanchions and crushed him.

Harry Jr., like the late Harry Sr., looks the part, but the son is not merely the younger version of the father. His black patent leather hair is spectrums away from the waves of white that rolled from his father's forehead in his later years, and he is a hefty man while his father was slight.

There are certain similarities. On stage, Harry Jr. often wears spangled, colorful tuxedos rather than his father's sedate tie and tails, but when he's off duty his black suit and white shirt faintly echo the somber cutaway. The son cultivates the predictable goatee; the father had an equally stylized mustache. And the eyes are the same magicians' eyes. With just a debonair lift of the brow and a tightening of the lids, that by now almost comically familiar expression endemic to magicians appears. Intense. Flashing. Capable, it seems, of emitting a concentrated beam of pure magic. You can imagine the son practicing in front of the mirror 'til he'd copied it exactly.

But on stage, Harry Jr. says, the differences outnumber the similarities.

"I have a totally different style," says Blackstone. "He was a much more classical type of performer than I am. Much straighter. I do a great deal of facetious comedy and audience participation. It's just the way my personality developed. Sometimes things can go wrong. You've heard the old saying things tend to go wrong at the worst possible moment. Well, that seems to happen a lot in magic and you learn to work your way out of it, and comedy is an easy way to work your way out of it."

Magic goes back three generations in his family. It began when, as a child in Chicago, his father had a newsstand outside the theater where the famous magician Harry Kellar was a regular performer.

"Oftentimes, rather than going right home, he would go in and watch the performance," says Harry Jr. His deep, resonant voice, trained in magic and radio, frequently wraps itself around the archaic words of storytelling, words like "oftentimes." For a magician, after all, the words and tone are as important as the eyes. Soothing and distracting at the same time, they keep the audience's gaze from his hands, where a bird is about to appear or a rabbit in the process of turning into a box of candy.

Harry Sr.'s father decided to check out the act that so captured his son's imagination, and then Harry's brother Pete was drawn in.

"They began this hobby of magic, building little things, reading books that were available in the library," says Harry Jr. "Finally, when my father figured he'd had enough education -- which was during the eighth grade -- he went to work for a woodworking shop. And one of the customers of this woodworking shop was the Roteberg Magic Company, and when they would order props my father was one of the several young people who would make them. Well, when Roteberg would order 10, my father would make 11, keeping one of them, and that was the way he began to build his repertory and build his supply of apparatus."

Kellar had offered to give Harry Sr. a job in his traveling show when he turned 14. So, on his 14th birthday, he went in search of the magician, found him in Wheeling, W. Va., and reminded him of the offer. He was given a job, but several weeks later, when the tour returned to Chicago, his mother reclaimed him, sent him back to school and told him to stick around until he was 21. At 21, he and Pete left for St. Paul, where the two brothers performed magic between performances of "The Great Robbery." Born the Boughton boys, for the show they changed the name to Bouton.

"The French was, I think, a desirable thing," says Harry Jr. "Well, nobody could remember the name. The time came a few months later, when a poster printer in Chicago said he had some posters and advertising paper that had been made for a magician who had decided to retire. My dad considered it, and several years later he went ahead and bought the paper. The paper was for Frederick the Great. His timing was impeccable because about six weeks later we were at war with Kaiser Wilhelm, whose father's name was Frederick the Great. Well, the rather severe anti-Germanic feeling in the Midwest at that time really kept my father from getting any bookings, so he and Pete had to decide on another name."

In a town in Connecticut, they found it.

"There was this sign on the far side of the square opposite this little theater where they were playing. Pete said, 'Harry, we need to find a name that's as easy to read as that sign.' The sign said, 'Blackstone's Cigars.' So, my dad said, 'No, I don't think Cigar the Magician will be such a good name' -- that was his sense of humor. So they went out in the name of Blackstone."

The show became the largest traveling magic show in the country.

Harry Jr. didn't expect to follow his father into a career of magic. "I really grew up in the ambiance of it," he says. Sometimes he assisted his father on stage and in the '40s appeared inside a manically grinning cat suit in a publicity shot; but he spent most of his youth in military academies while his parents toured with the Blackstone show.

Before he returned to professional magic, Harry Jr. had worked in broadcasting, politics and television. An employe on a Texas radio station owned by Lyndon Johnson, he went on to work in communications for Johnson, first on the campaign trail in 1960 and then in Washington. After 18 months he left. Later, he produced the Smothers Brothers' Comedy Hour on CBS. Only after the show was canceled in 1969, when Tommy Smothers asked him to provide the magic for his nightclub act and then offered to cosign a loan to help him get started, did Harry Jr. return to magic.

"I know my father was pleased," he says.

Before Harry Jr. became a professional magician, he received a master of fine arts degree in history of the theater. The history of magic still fascinates him.

"You can take magic back 4,500 years," he says. "It was part of the court performances in the Middle Dynasty in Egypt. There was a chap named Dedi who performed light entertainment magic, where he would move the head of a duck and the head of a pelican and switch them and put the pelican's head on the duck and the duck's head on the pelican. Well, that may sound rather esoteric and impossible, but it was being done as late as the 17th century, where they would change a pigeon's head and a duck's head.

"It's no longer done because, I think, the sensibilities of people nowadays and the concern that we have for our fellow animals on this planet preclude that as an entertainment. We do the same sorts of things, but we do them in a different way. It's not quite so sympathetically uncomfortable."

Now, he says, "The one thing that is lacking is a really top-notch lady magician. The women magicians that have been successful really number probably a half dozen. To me it's amazing, and I don't have an answer. I once asked one of the gals who did an act, 'Why is it that there aren't more women magicians?' She said, 'It's because of the wardrobe. You know that cutaway suit all men wear? That's what was used to develop so many of the illusions and the tricks that were done.' The way she put it was, 'In the costumes women have to wear on stage, there's no place for them to hide their bird, or whatever they need.'

"I think the best reason I can figure is that for so many centuries, magic -- which is an extension of the religious experience -- that magic, like religion, has depended on a male, if you will, father-type image. And when women started to enter into that area, they were looked on as interlopers. I think when we accept women priests and women in high positions in government and other than in the traditional and cliche'd positions that they have relegated themselves to, then there will be more women magicians.

"This is already happening, which is why there are more women magicians than there have ever been. In the past, the few were rather severe, butch types, and it wasn't good either for them or for the image of the industry. But now we find very feminine, attractive, well-trained young ladies who are getting in the business. They add music, they add glamor, all those things that are part of the business."

Harry Jr.'s life has been filled with women in their skimpy, magic-act costumes. His mother was an assistant in the original Blackstone show, his wife assists in his. "The Blackstone Book of Magic and Illusion" is filled with photo captions like, "My father pictured with his beautiful assistants."

And at home, if anyone is to continue the Blackstone tradition, it will probably be his 16-year-old daughter, Tracey.

"At least," he says, "when there are chores to do at home, she disappears."