In a used book store I opened the cover of an old book, to find that it had once belonged to one of Canada's major department stores. The use of the apostrophe indicates this was pre-1972. This was a different era of retail, when companies took care of their people, imagine Walmart actually maintaining an in-house library!
Simpson's was in business from 1858 till the early 1980s when it was acquired by its competitor, the Hudson Bay company. It was half owner of the popular Simpsons Sears (later Sears Canada) chain begun as a partnership with Sears Roebuck in the early 1950s. The last vestige of this empire is barely hanging on, Sears Canada having recently filed for bankruptcy.