Stewart, 73, was made very wealthy by the success of his textbooks and used his money to support various philanthropic projects, mostly involving music and mathematics. In Toronto, he is known for the development of Integral House, a $32 million dollar architectural wonder which served as his residence and a state-of-the-art concert facility for 150 people with perfect acoustics and dramatic curves.
Sadly, in 2013 Stewart was diagnosed with multiple myeloma and given a year to live; he succumbed to the disease earlier this month on December 3, 2014.
Toronto's The Globe and Mail reports:
The house and all its custom-designed furnishings were an expression of his love of curves, so prominent in calculus. But there was no “formula” for the house, he said – it was a work of art that he was lucky enough to live in, and that brought him into contact with musicians he might otherwise never have met.
It also became a great party centre during Pride Week and at Halloween, when the all-male guests were expected to show up in extravagant drag. “He was a crazy guy, privately,” Mr. Ralph says. “That man could party. He would let it all go.”
Dr. Stewart was “out” his whole adult life, and supported many services and initiatives for LGBT people. Joseph Clement, who is making a documentary about Integral House and its owner, said that in the early 1970s, Dr. Stewart helped launch the Pride movement in Hamilton by inviting Toronto activist George Hislop to speak in the city.As a gay mathematician myself I had heard that Stewart was gay but had not seen any documentation of this fact. It's sort of sad that fact is becoming more well-known now that Stewart is dead, but it is still an encouraging notion that a gay man was responsible for teaching generations of college students calculus.