Gardner's first two published novels, The Resurrection (1966) and The Wreckage of Agathon (1970) generated little response, although Geoffrey Wolff did praise the latter in Newsweek. With Grendel (1971), however, as David Cowart noted in Arches and Light, "the critical tide of caution began to turn. Reviewers were charmed, and Time and Newsweek cited it among the year's best novels. After a first printing of 7500 copies, it went through nine hardback and thirteen paperback printings in this country and England by the end of 1977. It had also, by then, been translated into French, Spanish, and Swedish." No doubt some of this attention was due to readers' familiarity with Grendel's literary source, the classic epic poem Beowulf, known especially to high school and college English students and their professors. Academics in particular respected the author, who was already an established scholar in medieval studies, having edited four books and translated two other works in this field.

But critics generally also felt, as David Cowart wrote in the Dictionary of Literary Biography, that in Grendel Gardner "burnishes the classic at the same time that he creates a new masterpiece." Academic critics in particular responded to Gardner's scholarship in drawing not only on medieval sources but also poets from William Blake to Thomas Kinsella and philosophers from Plato to Whitehead and Sartre. Critics also relished unravelling the novel's structure, with its allusions to the signs of the zodiac and various schools of philosophical thought. The character of Grendel received special attention, with a lively debate ensuing over whether that monster, who is certainly the central character in the story, is not also its real hero. Like the Shaper, Grendel is engaged in a struggle to create poetry. (As these critics noted, Beowulf, the ostensible hero of the novel, makes only a relatively brief appearance toward the end.) Some critics went as far as to consider Grendel an absurd hero whose violent nihilism is the only sane reaction to the chaos of modern society.

Gardner himself lent insight into this debate in his treatise On Moral Fiction. In this 1978 work (which according to New York Times Magazine contributor Stephen Singular was actually written in 1965), Gardner criticized contemporary novelists like Saul Bellow John Barth John Updike and Thomas Pynchon for not practicing "moral art." By this term he meant art which "in its highest form holds up models of virtue, whether they be heroic models like Homer's Achilles or models of quiet endurance like the coal miners ... in the photographs of W. Eugene Smith." In a similar vein, a year earlier Gardner had told Atlantic Monthly interviewers Don Edwards and Carol Polsgrove that "if we celebrate bad values in our arts, we're going to have a bad society. If we celebrate values which make you healthier, which make life better, we're going to have a better world." These statements would seem to indicate the author's intent lay in rebuking Grendel's nihilist viewpoints. That the work has been interpreted in exactly the opposite fashion is, according to various critics, either a testament to Gardner's ability to invent a powerful and sympathetic protagonist or an indication of his problems in clearly presenting his ideas.

Despite the fervency and high-mindedness of such views, On Modern Fiction elicited mostly negative reactions from both reviewers and fellow writers, as summarized by Cowart in Arches and Light. Not surprisingly, the novelists who were attacked in the essay fought back in print in widely read forums like the New York Times . And since Gardner had boldly and unapologetically set a high standard...