This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book examines metaphor and epiphany as techniques of umorismo: It is a study of the first of these heuristic devices, which Pirandello uses obsessively to create allusive intertextual relations between 'L'umorismo' and his narrative. It looks at narrative epiphany as theorized in 'L'umorismo' and elsewhere, again as a specifically metatextual phenomenon, intimately linked to the creativity of the artist. The book focuses on three Pirandello novels: it have excluded from discussion L'esclusa, Il turno, Il fu Mattia Pascal and Quaderni di Serafino Gubbio, partly for obvious reasons of space, which preclude an exhaustive survey of Pirandello's novels. The book also interrogates Uno, nessuno's status as touchstone of Pirandello's narrative production. Again, an examination of its sources is rewarding: they are, as is known, earlier versions or 'pre-texts' of the novel.