Anarchist criminology is a school of thought in criminology that draws on influences and insights from anarchist theory and practice. Building on insights from anarchist theorists including Pierre-Joseph Proudhon and Peter Kropotkin, anarchist criminologists' approach to the causes of crime emphasises what they argue are the harmful effects of the state. Anarchist criminologists, a number of whom have produced work in the field since the 1970s, have critiqued the political underpinnings of criminology and emphasised the political significance of forms of crime not ordinarily considered to be political. Anarchists propose the abolition of the state; accordingly, anarchist criminologists tend to argue in favour of forms of non-state justice. The principles and arguments of anarchist criminology share certain features with those of Marxist criminology, critical criminology and other schools of thought within the discipline, while also differing in certain respects.