This book aims to make known, in a detailed but accessible way to the general public, an old idea, but which has had renewed interest in recent years: the proposal to grant an unconditional basic income for all. This idea, often discarded and disqualified for allegedly belonging to the mere domain of utopia, understood in a pejorative sense as something unrealizable, has been the target of the interest of many people (academics, politicians, businessmen, activists, and, obviously, all citizens concerned with the common good) and presented as being feasible through various concrete experiences and pilot projects.