James Stewart is a calculus rock star.

When he goes on book tours in China, they ask for his autograph. In Toronto, the city’s movers and shakers gather at his home for concerts. People have drunkenly stumbled into his infinity pool.

Stewart’s 18,000-square-foot home, named Integral House, is an architectural marvel. It has five floors, a concert space and a stairwell ensconced in handblown blue glass, his favourite colour. The house is filled with gadgets. Stewart delights in showing them off, including the wall to wall blinds that block out the sun with a push of a button in his treetop bedroom.

PHOTOS: INTEGRAL HOUSE



“I don’t like to wake up too early,” he says.

Rosedale is a neighbourhood of riches, but Stewart’s are of a peculiar design. In 1987 he published his first calculus text book. Today, 90 per cent of Canadian university students use his books, and 70 per cent of U.S. students do the same. The bestselling books have been translated into 12 languages. He’s a bit like John Grisham, if Grisham knew how to write good sigma notation.

“I would not have predicted it,” says the fair-haired Stewart, ever the mathematician.

Stewart is from Toronto. His brother and sister aren’t mathematical at all. His father was an engineer. His mother was an artist.

As a boy, Stewart loved music and math. At the University of Toronto, he almost switched into music during second year university. But he stuck with math and played the violin on the side.

In the 80s, Stewart split his time between playing violin in the Hamilton Philharmonic Orchestra and trying to make calculus digestible for undergrads at McMaster. One day, some of his students told him he should write a book, since his blackboard lesson made more sense than the text they were using.

Stewart spent the next seven years in exile and wrote the kind of book he’d like to use. When it was finished, the book stood out for being easy to understand. It was a bestseller by 1992.

“There are no brochures in guidance offices for textbook writers,” he says as his feet rest on the heated limestone floors.

With money pouring in with each new edition, Stewart renovated homes in Hamilton, and later, in Toronto. He wanted his final home to be his masterpiece.

He travelled the world to interview architects, including Frank Gehry. He chose Howard Sutcliffe and Brigitte Shim of Shim-Sutcliffe Architects in Toronto, and told them he wanted curves and performance space. He let them imagine the rest.

There are some numbers Stewart doesn’t like to talk about. One is his age. Another is the cost of his home. Estimates have pegged it at $30 million.

Stewart bought a $5.4 million house that backs on to the ravine in Rosedale in 2002 and tore it down a year later. Integral House took six years to build, on account of its curves.

From the street, only two stories are visible. The main living space was built one floor below street level so it feels like you’re descending into the ravine. The back half of the house is glass mixed with oak fins. The house has minimal interior decoration — the trees outside are the real focal point. They are visible from all five floors.

“The aspiration is that the project feels timeless,” architect Brigitte Shim said.

The director of New York’s Museum of Modern Art called Stewart’s home one of the “most important private houses” in North America.

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The floors are made of limestone from France. Before installing the floor, the architects tested the limestone with red wine, coffee and cola. It came off no problem, but when it was installed, the seal wasn’t as strong.

“At the first fundraiser held here, guests dropped their glasses of red wine, I said, ‘Not to worry, these tests prove it will come off,’ but it didn’t.” Red wine is now outlawed at receptions.

Although it’s just Stewart who lives there, with the occasional friend staying in the house’s two-bedroom apartment, Toronto’s arts community is also a de facto inhabitant.

The concert space was built for Stewart to host 150-person concerts, but he did not anticipate his house would become the darling of fundraising circles.

“I turn down more requests than I get,” he said. “I usually put on eight events per year. I choose the causes that resonate with me.”

Small theatre groups, music festivals, dance companies, and fashion entrepreneurs have all used the house for benefits. Stewart has been thrilled to meet some of his heroes along the way.

American composer Steve Reich has played here, and Phillip Glass, a renowned composer whose work has been nominated for Academy Awards, is expected to stop by this year.

Shim, who attends many of the events, is continually impressed.

“He’s just a really lovely guy, the nicest person you ever want to meet,” she said of Stewart.

The house may have catapulted Stewart into circles most mathletes don’t travel in, but he’s still a professor at heart. When he came home from a walk to find two architecture students peering into his windows, he gave them a tour.

After all, this is the house that math built, and calculus is a beautiful thing to share.