The Blazing World was the first utopia in English written by a woman, and likely, the first science fiction text in English. Yet it was not Margaret Cavendish’s only utopic text. The separatist spaces of her plays, and the virtual communities of her epistolary collections, were earlier utopias that contributed to her construction of Blazing World. Cavendish established the characteristics of utopian literature through the transgression of categories and hybridity. I consider her blurring of genus, genre and gender in two of her utopic texts, Sociable Letters and Blazing World, and her strategic development of the blurring of these categories.