Walter Shawlee, of Kelowna, British Columbia, is only one of a group of slide rule aficionados but, according to Pui-Wing Tam, he’s referred to as "Mr. Slide Rule," and may have the most extensive collection on the planet. Writing in The Wall Street Journal recently, Pui-Wing reports that Shawlee taps a network of international contacts to buy and sell these venerable mathematical instruments. At any one time, he may have 3,000 slide rules in stock, many in mint condition and in their original boxes, and others that he has painstakingly restored.
Some teachers are reintroducing slide rules in their classrooms, Pui-Wing says, arguing that they foster more complex thought processes than electronic calculators. Joseph Pasquale, Ph.D., a professor of computer science and engineering at the University of CaliforniaSan Diego, launched a freshman seminar on slide rules in January. "I always thought we lost something when we stopped using slide rules," he says. "They’re so much more an extension of your mind than a replacement."