Human history has always been marked by the mobility of people and populations, from the earliest movement of human beings out of Africa to the flows of migrants and refugees today. While mobility is intrinsic to human nature, migration is not always voluntary: it can be the result of free choice, but it can also be forced, in different ways and to varying degrees. In this book, Massimo Livi-Bacci examines migrations past and present with reference to the degree of free choice behind them. The degree can be minimal, as when migration is compelled by war, natural disaster or the actions of a tyrant, but in other cases the decision to migrate can be fully voluntary and deliberate, as when individuals and groups weigh up their options and decide whether to move. Between these two poles there is a continuum of different situations, with gradually increasing or decreasing degrees of freedom and choice. Livi-Bacci explores these variations by focusing on fifteen stories of migration from Antiquity to the present day, ranging from the Greek colonization of the Eastern Mediterranean in the Ancient world to the great migration of millions of people from Europe to the Americas in the nineteenth and twentieth centuries. Taken together, these stories of human movement shed fresh light on the millennia-long history of migration and its motivations, causes and consequences.