Book excerpt: This book address the relationship between utopian and radical thought, particularly in the early modern period, and puts forward alternatives approaches to imagined ‘realities’. Alternative Worlds Imagined, 1500-1700 explores the nature and meaning of radicalism in a traditional society; the necessity of fiction both in rejecting and constructing the status quo; and the circumstances in which radical and utopian fictions appear to become imperative. In particular, it closely examines non-violence in Gerrard Winstanley’s thought; millennialism and utopianism as mutual critiques; form and substance in early modern utopianism/radicalism; Thomas More’s utopian theatre of interests; and James Harrington and the political necessity of narrative fiction. This detailed analysis underpins observations about the longer term historical significance and meaning of both radicalism and utopianism.