T.S. Eliot 's contributions to twentieth-century literature are complex, far reaching, and of perhaps greater import than those of any other major literary figure of the period. His poems created a revolution in and revaluation of the world of poetry, and his essays introduced fresh ways of looking at literature, shed a new and sometimes brighter light on specific writers and their works, and discussed significant social and religious issues. In the field of drama, he attempted to reestablish poetic drama as a vital force in the theatre. His interest in drama spanned almost his entire literary career, beginning in the early 1920s with several important essays on poetic drama and ending in the late 1950s with The Elder Statesman (1958); during this time, he wrote seven plays as well as more than thirty essays on the theory of drama, on dramatists, and on specific plays. These works reveal a conscious craftsman and a tireless experimenter; they set before us the definite goal toward which he constantly strove, what in "Poetry and Drama" he calls "an unattainable ideal," "a kind of mirage of the perfection of verse drama"; and they delve beneath the everyday world to the deeper, more elusive, but altogether more significant realities of the spiritual world.