This study explores Heinrich Böll's 'aesthetic thinking', as it is expressed in the author's disparate and voluminous writings on literature. Böll's work in this field is situated in the multi-faceted context of social, political, and cultural developments in post-war Germany, and is shown to be an important adjunct to the novels and stories which were honoured with the Nobel Prize for Literature.An understanding of Heinrich Böll's 'aesthetic thinking' can illuminate the writer's fiction in an intriguing way. In particular, Böll's defence of the 'rationality of poetry' raises issues which reverberate in continuing debates on the social validity of literature.