His 1977 text, Cognitive-behaviour Modification: An Integrative Approach, contributed to the development of cognitive behaviour therapy, transforming how illnesses like obsessive-compulsive disorder are treated.
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How Canada's IMAX went from a high-school lab to 1,000 theatres worldwide
Science teacher Gordon Clark gave three of his students the run of the high-school lab after hours in the 1940s, he would have had no idea that they would come up with one of the biggest innovations.