This doctoral dissertation provides a theoretical examination of amateur craft as a differential practice. Concepts drawn from an inter-disciplinary source base are used to define, characterise and elucidate features of amateur craft practice that have long been presumed superfluous and opposite to valorised 'professional' practice. I investigate the attraction, motivation and complexities that lie behind this widespread, yet largely understudied, phenomenon of modern culture. Studies of everyday life, social history, aesthetics, material culture, art criticism and craft theory help conceptualise the position of the amateur, and case studies from the nineteenth and twentieth centuries - including the paint-by-number mania in 1950s USA, suburban chicken keeping, and amateur railway modelling - serve to substantiate the theoretical claims made. The thesis is not comprehensive in its coverage of either a specific craft medium or a particular chronology or geography. Instead the thesis is divided into three thematic chapters: amateur surface intervention, amateur space, and amateur time. These chapters reveal some of the unexpected consequences of subjecting amateur practice to serious study. The examples demonstrate how amateur craft practice is differential within capitalism,dependant on its structures while simultaneously stretching, refracting, and quietly subverting them. As a reprieve or a supplement to an individual's primary occupation, the constrained freedom of amateur craft practice fulfils an essential role within modern life, providing a temporary moment of autonomous control over labour-power in which the world can be shaped anew.