Bob Junior is currently in London, laying the foundations for his own transatlantic media empire, which began last month with the launch of Gear, an upmarket men's magazine, financed with the proceeds of the sale of Spin, a music magazine he founded, and which he sold last year for $43m.
It must be tough growing up as the eldest son of a powerful, patrician Sicilian-American whose infamy, a generation ago, dwarfed that of Hugh Hefner. As an 11-year-old walking home from school in London, Bob Jr saw newspaper posters announcing "pornographer to be deported to America" without realising they were talking about his dad.
"I idolised my dad totally when I was a kid," he says. "Of course, I wanted to become the publisher of Penthouse when I grew up." It was a feeling he was to grow out of only slowly, in his twenties.
Born in Manhattan, he spent his childhood in London after his father, then an artist, moved over with his English wife Muriel. Bob Jr retains an Anglicised accent, though with the Italianate emphasis you hear in Scorsese films.
Family life was not, he insists, influenced by the world of Pets of the Month at Daddy's office. "He did a good job of teaching us the difference between fantasy and reality."
Still, some influences have worn off: a bachelor at 43, Mr Guccione Jr is, according to all who know him, a great admirer of women. But for someone who is both a self-made multimillionaire and the son of one of America's brasher tycoons, Bob Jr can be curiously, engagingly insecure. He always wanted to be a writer, he says, but never considered himself good enough. He looks and acts younger than his 43 years, not affecting the authority of middle age; he is unashamed to sound inquisitively naive. But Mr Guccione Jr also has the mercurial intuition of a self-taught man, anticipating questions and answering them with an impressive articulacy.
In his twenties, Bob Jr worked at Penthouse, lining up, as his father wanted, to take control some time in the future. But then he decided that he'd had enough. The key factor wasn't Penthouse itself, towards which he remains ambivalent: "I wasn't ashamed of what my father did, at all. I just don't care for nude magazines because my own life is interesting enough."
Spin, the music magazine he started in 1985, wasn't exactly his own thing at first: it was financed by his father. But three years later, the crisis happened.
"In 1988, Penthouse was under siege from the moral majority and losing sales. It had to rethink its investments and Spin was one of them. At a certain point my father and I... clashed. The rest," he pauses, "was just family matters."
He will say little more, save that his father gave the staff of Spin, including his son, eight hours to move out of the building, and hasn't spoken a word to him since. The 32-year-old was left without an office or an administrative staff.
"I had to start again. I remember sitting on a roof one day and thinking, `This magazine is my baby; I don't want it to die.' It was very tough, but I was 32 and I thought, if I'm not my own man now, I'll never be. Besides," he says, smiling, "I didn't have much choice, did I? I was unemployed."
Not only was he jobless, but also, after three decades of living for a domineering father, he was fatherless. "I felt abandoned, but if I'd dwelt on it I wouldn't have had the strength to go on."
After nine years of Mr Guccione Jr and his 17 staff putting in 100-hour weeks, Spin had, by last year, become a huge success as an irreverent alternative to Rolling Stone, playing the quirky upstart to its rival's establishment conformism. The musician Quincy Jones bought it for $43m and its founder, who had never been wealthy until then, walked away with $17m.
"I could have just stopped working for the rest of my life," he says, now sounding more like a publishing magnate, "but I love my work, and I want to use my talent."
So, earlier this year, with the help of Sue Douglas, formerly editor of The Sunday Express, Mr Guccione Jr headed closer to the family home with the launch in the United States of Gear, a men's magazine that, he says, "is countering the gaggingly PC men's magazine market in the US, which is characterised by stiffness and humourlessness".
"In the UK nobody's heard of me, but in the States," Mr Guccione Jr says proudly, "I'm well respected in my own terms."
A British version of Gear may be on the cards and Mr Guccione Jr makes no secret of his empire-building ambitions.
"I want to build a large, exciting, adventurous media company," he says. "The magazines will all be fun for the consumer, fun to do. I don't want to start a family of golfing magazines."
The rise of Guccione Minor comes at the same time as the decline of Guccione Major. Penthouse has been making a loss, besieged on one side by the forces of political correctness and on the other by the proliferation of the American hard-core pornography industry. But the son takes no pleasure in his father's troubled times: "If I'd done all this just to show my dad that I can do it too, it would have been too shallow a reason to sustain itself.
"I hear," he adds, "that sometimes he enquires about me from my family - fondly, almost as if I'm dead. But he's never made any comment about what I do.
"I still love him and I hope that deep down he loves me," says the new tycoon. He looks up, gazing through me into the middle distance. "I hope one day we can reconcile."Reuse content