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? Johannes Kabderian Dreyer is an Associate Professor of Financial Economics at Roskilde University, Denmark. He earned his bachelor's degree in Economics and his master's in Finance at the Pontifical Catholic University of Rio de Janeiro, Brazil. He received his doctorate in Financial Economics from the Catholic University of Eichstätt-Ingolstadt, Germany. Peter Alfons Schmid is a Professor of Business Administration at the FOM University of Applied Sciences, Germany. He holds a diploma degree and doctorate from the Catholic University of Eichstätt-Ingolstadt, Germany. He was a teaching and research assistant, worked as a professional at global and regional accounting firms and developed a tech start-up.