Working across disciplines and national boundaries, the contributors to this volume argue that policy prioritization in the fields of peacebuilding, development, and human security by Tokyo and Seoul could have the potential to accrue wider benefits not only to the Northeast Asian actors and the Southeast Asian partners, but also to wider regional and even global security communities. At a time when the role of so-called middle powers is receiving increasing levels of attention both domestically and internationally, this book will be of considerable interest to scholars of Japan and the ROK, as well as development, security, and foreign policy researchers more broadly.