This book addresses a longstanding issue that emerged fifty years ago and continues to persist– the lack of an accounting and reporting system for financial sustainability. Consequently, the primary aim of this book is to develop a novel accounting and reporting system for measuring and reporting long-term financial sustainability in the public sector. The significance of this book lies in its introduction of an innovative role within the field of accounting. This role entails providing guidance and issuing alerts to governments regarding essential adjustments needed in current policies to ensure the long-term financial sustainability of governmental entities. Through elucidating the prospective trajectory of public finance within the ongoing implementation of current policies, this approach functions as an early warning system for governments and empowering them to proactively modify their policies and transition from unsustainable scenarios to sustainable ones. The primary audience for this book includes practitioners, academics, students, professional bodies, and various users of accounting information in the public sector, such as public managers and policymakers seeking accounting information for corrective measures. Additionally, international organizations like the IMF and World Bank, tasked with assessing countries' long-term financial sustainability, will find this work indispensable.