In the past decade, Germany, the Netherlands and the United Kingdom have formalised or introduced language and knowledge of society tests for immigrants applying for citizenship. The aim of this book is to assess the explicit and hidden goals these citizenship tests are meant to achieve, as well as to analyse their intended and unintended effects. The book answers the questions of why the countries under consideration introduced citizenship tests and what effects these tests have produced. The latter question has been answered on the basis of an analysis of relevant statistics and an analysis of interviews with immigrants and stakeholders. Furthermore, the content of the tests presented to (possible) future citizens of Germany, the Netherlands and the UK has been thoroughly analysed.