<p>This book analyses business cycles synchronization in the Euro Area (EA), one of the 3 criteria that define Optimal Currency Areas (OCAs). Even before its launch, economists questioned whether the EA has what it takes to become an OCA. The onset of the sovereign debt crisis in 2010 confirmed the challenges relating to its construction. But did the EA change over time, and what key drivers may be necessary in the future to strengthen the common currency?</p>