Direction : Read the passage carefully and answer the questions given below based solely on the passage :

Passage I

When Elizabeth Long began investigating women's book groups in the mid-1980s, her research plan provoked two profoundly different sets of reactions. Women, who had themselves participated in such groups, as well as men whose mothers and grandmothers had done so, immediately grasped the importance of her project : "You will never know what a difference it made" was the phrase she heard again and again. But among her academic colleagues, common readers seemed to be occupying a zone of cultural invisibility. They were not of interest to literature departments, whose major focus is on books and authors, not readers. They were not of interest to sociologists or political scientists because women's reading groups do not pursue activities with any obvious relationship to formal political processes. Long, however, went on to show that such groups had mobilised the women's suffrage and Progressive movements at the grassroots. Scholars of popular culture had not found reading groups interesting because the groups read canonized fiction and did not transform their cultural consumption into a 'resistant' subcultural style. It had not yet occurred to them that the so-called highbrow canonical literature could be immensely popular and devilishly subversive. David Vincent's Bread, Knowledge and Freedom (1981) had already demonstrated the important role of reading in inspiring working-class consciousness in early nineteenth-century Britain. As a sociologist, Long concluded that the really important question that needed answering was why academics did not care about readers.

In this passage, "canonical literature" refers to :