Based on an analysis of two experimental novels of the 19th Century - The Elective Affinities (1809) by Johann Wolfgang Goethe and Bouvard et Pécuchet (1880/81) by Gustave Flaubert, this dissertation aims at making a contribution to both existing research on fictional encyclopaedias and, more largely, to the study of the complex relationships between literature, science and knowledge. The first chapter introduces current theoretical debates on the relation-ships between literary theory and the history of science. It discusses existing theoretical approaches to encyclopaedic literature at hand as well as their attempts at giving a definition of an encyclopaedic novel. The second chapter traces the social and intellectual history of encyclopaedia from its roots in the baroque era to the late 19th Century. It offers a detailed analyses of a specific discourse that reflected the human strive to collect, order and systematize knowledge. Analysing in detail the reception of Goethe by Flaubert shows that Goethean universalism and his objective writing have strongly influenced the reception of the German writer in the late nineteenth century France. Focusing on the figures of the knowing subject, encyclopaedic spaces, themes and motifs, my analyses of both texts reveals how both authors take similar formal decisions when addressing en cyclopaedic issues in the novel. Among the various fields of knowledge that are embraced in both novels, I focus on three areas of knowledge - chemistry, education and botany, that embodied the new scientific spirit of the 19th Century, as well as three different forms of reflection on and criticism of the encyclopaedic project.