This volume integrates historical and policy-oriented papers dealing with the relevance of the Keynesian approach for economic theory, policy, and crisis analysis. The first part of the volume focuses on historical, theoretical, and methodological issues, putting them in current codex. The second part focuses on the application of the Keynesian approach to modeling the economy, policy-making, and analyzing the ongoing crisis of the early 21st century. Papers by leading macroeconomists, such as Laidle, Cukierman, Colander and Boyer are complemented by those of leading historians of economics, such as Hollander, Boianovsky, Marcuzzo, Dimand, Witztum, Young, deVroey and Arnon and provide a comprehensive evaluation of the current relevance of Keynesian Economics. One of the important features of the volume are the commentaries on the papgers, which provide a cross-fertilisation between macroeconomists and historians of economics, which in conjunction with the paper themselves, provide a fair and balanced outlook on the current relevance of Keynesian Economics.