A black swan is an event, positive or negative, that is deemed improbable yetcauses massive consequences. In this groundbreaking and prophetic book, Talebshows in a playful way that black swan events explain almost everything aboutour world. Annotation: A black swan is an event, positive or negative, that is deemed improbable yetcauses massive consequences. In this groundbreaking and prophetic book, Talebshows in a playful way that black swan events explain almost everything aboutour world.