The main aim of this book is to evaluate the US foreign policy during the Trump era and its ultra-nationalism within the context of its influence on the major actors and regions at the international level. The authoritarian dimension of the Trump administration's policy will be the supportive element of the framework of this book. The events in the US move very quickly nowadays in terms of Trump's authoritarianism, despite all the natural shortcomings. We hope that this book will serve as a guide to understand Trump's US foreign policy.