This highly original study of the "manic style" in enthusiastic writing of the seventeenth and eighteenth centuries identifies a line of influence running from the radical visionary and prophetic writing of the Ranters and their fellows enthusiasts to the work of Jonathan Swift and Christopher Smart. Its account of the dominant culture's ridicule of enthusiastic writing (an attitude that persists in twentieth-century literary history and criticism) provides a powerful and daring critique of pervasive assumptions about madness and sanity in literature.