States claim the right to choose who can come to their country. They put up barriers and expose migrants to deadly journeys. Those who survive are labelled 'illegal' and find themselves vulnerable and unrepresented. The international state system advantages the lucky few born in rich countries and locks others into poor and often repressive ones. In this book, Christopher Bertram skilfully weaves a lucid exposition of the debates in political philosophy with original insights to argue that migration controls must be justifiable to everyone, including would-be and actual immigrants. Until justice prevails, states have no credible right to exclude and no-one is obliged to obey their immigration rules. Bertram's analysis powerfully cuts through the fog of political rhetoric that obscures this controversial topic. It will be essential reading for anyone interested in the politics and ethics of migration.