This book provides an overview of public policy, but rather than describing a country's policies, it deals with explanations for each area. By doing so, basic concepts, issues related to policy effectiveness, and approaches reveal researchers' methods in describing its characteristics. In this way, the book explores how public policies and policy systems are performing sector by sector among developed countries. It will be clarified by many examples of how different the so-called "society" to which this document is directed includes developing countries and OECD member countries. This book also shows that public policy is still growing in the process that needs to be covered, and government, where public policies are undergoing drastic changes to allow optimism. Therefore, it cannot be handled either. The examples dealt with in this book are issues that have been studied comparatively.