This book discusses current challenges in Japan, focusing on the nation’s rapidly aging population and low birth rate, along with persistent public bond issues with heavy interest payments, the potential collapse of social security systems, and income inequality, as well as the global picture. In turn, it examines the accessibility of global fossil fuels and feasibility of large-scale solar energy use. A new theory of money, interest, and capital is put forward, together with a proposal for an alternative system of international monetary cooperation, to promote a more sustainable and equitable world. Specific topics discussed include • the inverted population pyramid, due to the dramatic change in human life spans and declining birth rates; • the rapidly shrinking workforce, aging population, and declining GDP share sourced from industry; • disproportionate debt expansion due to public bond issues and coping with a persistent budget deficit; • the potential collapse of social security systems combined with income inequality; and • how to mitigate these bio-economic predicaments. offers an essential guide for policymakers, economists, researchers, and all those concerned with establishing a sustainable and equitable society from both energy and monetary perspectives. Further, it will be of interest to readers around the world, as the lessons learned from Japan are crucial to other developed societies that may eventually face the same types of challenge.