The aim of the present thesis is to examine the work of the Uruguayan novelist Juan Carlos Onetti (born 1909), a writer whose achievement is only now beginning to draw significant critical attention. Onetti's full range and complexity have not been adequately appreciated; little more than passing interest has been shown, for example, in his intricate uses of irony. Also deserving further study is the basic unity underlying the varied aspects of his fiction in which the alienated condition of the characters is directly connected with their creativity - expressed in such diverse forms as fantasy, farce and literary activity. Fantasy, farce and particularly literary activity assume positive value for Onetti, being presented as imperfect, though, to a certain extent, meaningful forms of salvation for the individuals who resort to them. Another major aspect of Onetti, his debt to William Faulkner whose influence upon him is considerable, has also attracted scant critical interest, and a further aim of the thesis is to analyze this important question and to consider in addition lesser influences on Onetti's work. The conclusion seeks to show that although his fiction owes a great deal to foreign influences, Onetti is nonetheless essentially an original writer, expressing his own individual world view which may at first sight appear unremittingly bleak but in reality shows definite though easily overlooked elements of hope and optimism.