This book examines the process of migration of medical doctors from Poland to the United Kingdom following the European Union expansion in 2004. The research covers all the stages of the process, from a study of the determinants, the decision-making process, through the channels of migration, to the reception in the host country and the impact on the sending country. The conceptual framework, largely based on the brain drain approach and push-pull model for evaluating mobility, is extended to include a more comprehensive study of the socio-political conditions, as well as micro, meso and macro theories from different disciplines in order to explain migration and its outcomes. A broad range of sources is used for the study, combining the analysis of official data and documents with original in-depth interviews with doctors who moved abroad and those who had no intention to do so, a quantitative survey measuring the migration propensity among medical students, as well as interviews with recruitment agents and key informants.