" Karl Jaspers' Theory of Irrationality: From Delusions to Worldviews is a substantive analysis and critique of Karl Jaspers' theory of irrationality. The nuanced exposition and interpretation of Jaspersian irrationality engages contemporary philosophers who espouse foundationalist, coherentist and normative understandings of irrationality. Daniel Adsett engages contemporary philosophers of reason with specific reference to Jaspers' distinction between 'delusions proper' and 'delusion-like ideas' (General Psychopathology) and convincingly argues the case for the irrationality of delusions as a form of 'incorrigibility.' The work teases out highly relevant implications of Jaspersian reason and irrationality for putative comprehensive reductionist worldviews that profess absolute knowledge of the individual (Psychoanalysis), world (Marxism) and God (dogmatic theology) and suggests the current-day relevance of Jaspers' account of irrationality for contemporary political discourses and new developments of artificial intelligence. While a sympathetic reading of Jaspers' theory of irrationality, Karl Jaspers' Theory of Irrationality closes with a compelling critique of the idea of 'the Encompassing' and method of 'Periechontology' that appeals to Jaspers' concept of 'Foundering' as a way to understand some of the tensive contradictions in Jaspersian philosophizing. Wide-ranging in scope, meticulous in reference, and well-written, Adsett's book deserves a wide readership and reception.".