Are migrant workers needed to 'do the jobs that locals will not do' or are they simply a more exploitable labour force? Do they have a better 'work ethic' or are they less able to complain? Is migrant labour the solution to 'skills shortages' or actually part of the problem? This book provides a comprehensive framework for analysing the demand for migrant workers in high-income countries. It demonstrates how a wide range of government policies, often unrelated to migration, contribute to creating a growing demand for migrant labour. This demand can persist even during economic downturns. The book includes quantitative and qualitative analyses of the changing role of migrants in the UK economy. The empirical chapters include in-depth examinations of the nature of staff shortages and the use of migrant workers in six sectors: health; social care; hospitality; food production; construction; and financial services. The book's conceptual framework and empirical findings are of importance to academic and policy debates about labour immigration in all high-income countries. The final chapter presents a comparative analysis of research and policy approaches to assessing labour shortages in the UK and the US. It examines the potential lessons of the UK's Migration Advisory Committee (MAC) for current debates about labour shortages and immigration reform in the US. The book will be of significant interest to policy-makers, stakeholders, academics and students.