Bolder economic policy could have addressed the persistent bouts of deflation in post-bubble Japan, claims this book. Despite warnings from economists, intense political pressure, and unconventional policy options to address this problem, Japan's central bank, the Bank of Japan (BOJ), resisted taking the bold actions that this book claims would have significantly helped. With Prime Minister Abe Shinzō's return to power, Japan finally shifted course at the start of 2013 with the launch of Abenomics—an economic agenda to reflate the economy—and Abe's appointment of new leadership at the BOJ. The BOJ's resistance to experimenting with bolder policy stemmed from entrenched policy ideas that were hostile to activist monetary policy. The book explains how these policy ideas evolved over the course of the BOJ's long history and gained dominance because of the closed nature of the broader policy network. The explanatory power of policy ideas and networks suggests a basic inadequacy in the dominant framework for analysis of the politics of monetary policy derived from the literature on central bank independence. This approach privileges the interaction between political principals and their supposed agents, central bankers; but this book shows clearly that central bankers' views, shaped by ideas and institutions, can be decisive in determining monetary policy. Through a combination of institutional analysis, quantitative empirical tests, in-depth case studies, and structured comparison of Japan with other countries, the book shows that, ultimately, the decision to adopt aggressive monetary policy depends largely on the bankers' established policy ideas and policy network.