The answer is: change intellect to intellectual.
The word that should be changed is intellect for intellectual. An intellectual is a person who has spent considerable time studying, reflecting and speculating in a broad range of topics and fields of knowledge, to the point where that person could be called an erudite.
The sense of the sentence is that the person in question believes himself to be an intellectual as defined above, but the books, and the topics of those books, reflect that, in reality, the depth of his knowledge is summarized in the contents of comic books and jokes, hardly the topic matters that an intellectual would master.