This book introduces geography, history, culture, economy and politics of North America, Latin America, France and Africa. Based on the analysis of these aspects, this book explores the possibility of unification between two geographically adjacent countries, which are the same or similar in history, culture, language and other aspects. Unification should promote economy and improve people's living condition. This book does not make such proposition that all geographically adjacent countries with the same or similar history, culture and language should be unified. Unification between countries involves too many issues. For most adjacent countries, unification between countries is simply impossible, even if they are the same or similar in history, culture, language and other aspects. In this book, exploration of unification involves Canada, USA, Mexico, Chile, Argentina, France, South Africa and some Central American countries. Unification should get the consent of the involved peoples and be achieved through peaceful means, not forces.