The European Union's enlargement process has arguably been Europe's greatest contribution to world peace and stability in the past 50 years. The incentive and then the reality of EU membership helped transform former military and communist dictatorships into prosperous and peaceful democracies from Portugal to Estonia. But as Grant shows in this monograph, EU enlargement is in trouble. After the accession of ten mostly former communist countries in 2004, and with European economies stagnant and leadership hard to find, public opinion is increasingly hostile to the enlargement process. Ukraine, the Balkans, the Caucasus, and Turkey all want to join, but it is not clear that EU populations want them. Grant supports further enlargement and has written a smart primer with lots of useful ideas on how to promote it in the long run and help the candidates in the meantime. The cause is noble, but this realistic assessment also underscores that it will be an uphill struggle.