One of Lefebvre's most important contributions to social thought is the idea of the "critique of everyday life", which he pioneered in the 1930s. Lefebvre defined everyday life dialectically as the intersection of "illusion and truth, power and helplessness; the intersection of the sector man controls and the sector he does not control", and is where the perpetually transformative conflict occurs between diverse, specific rhythms: the body's polyrhythmic bundles of natural rhythms, physiological (natural) rhythms, and social rhythms (Lefebvre and Régulier, 1985: 73). The everyday was, in short, the space in which all life occurred, and between which all fragmented activities took place. It was the residual. While the theme presented itself in many works, it was most notably outlined in his eponymous three-volume study, which came out in individual installments, decades apart, in 1947, 1961, and 1981.