The purpose of this study is to examine the rationale of Doris Lessing's development from classical realism to mysticism and forms of science fiction, and to consider the unifying motifs that appear throughout her novels in her consistent search for Sufi equilibrium. The selected novels represent significant stages in Lessing's work. Chapter one focuses on "The Grass is Singing", which represents the author's early, traditionally realistic writing, to show how far the preoccupations of Lessing's later novels find expression in this early work. Chapter two studies "The Golden Notebook", which marks a turning point in formal structure in Lessing's canon, and is selected as evidence of her interest in Sufism at that early stage. Chapter three concentrates on the study of "The Memoirs of a Survivor", which has elicited a comparatively limited amount of criticism, but which proves to be a major achievement when brought into line with Sufi methods of writing. Chapter four considers Lessing's science fiction series, "Canopus in Argos", trading sources from Oriental literature - a key which unlocks many areas of obscurity.