The thesis is based on the premise that an author who provides expressions of literary opinion by the characters in his fictional work will also include his own views among the others—explicitly, vicariously, or by demonstration. In Don Quixote, the purported attack on books of chivalry and the inclusion of poems and stories in variant styles provide justification for extensive commentaries on literary themes. To distinguish Cervantes' views among the diverse literary opinions expressed, such commentaries are evaluated on the basis of the information provided by the author as to the background and interests of the speakers— the characters, chronicler or narrator. Specific qualities carmended, condemned, or demonstrated are identified. Stories and serious poems inserted in the novel, and literary comment in Cervantes' Galatea and Viaje del Pamaso, are examined for corroboration or contradiction of the findings. Relevant opinions of several generations of twentieth-century critics are examined. Conclusions summarize—for Fiction, Poetry and Drama—the features which satisfy the stated requirement to "delight and instruct" and those to be avoided. A degree of ambivalence, between certain literary precepts which Cervantes promotes in Don Quixote and those demonstrated in his work, is identified. Special requirements for History are noted. Whether or not, under the respectable guise of an attack on books of chivalry, Cervantes sought to elevate the public taste in literature—an endeavour as quixotic as any undertaken by his protagonist—he claimed due recognition from the literary world for his perceptions of literary values and his competence as a writer.