Maths palace built by calculus 'rock star' on sale for £11.4m

James Stewart's calculus text books made him very rich. He spent his fortune on Integral House, an award-winning architectural marvel inspired by calculus, which is now on sale after he died last year

James Stewart was an unlikely literary sensation.

The Canadian mathematician made a multimillion-dollar fortune by writing calculus textbooks for universities and high schools. Last year alone he sold 500,000 books, accounting for about $26.6m (17.5m) in sales, according to his estate.