This book presents a new computational approach to solving large-scale Auerbach-Kotlikoff Overlapping Generations (OLG) models in a complementarity format. Unlike with integrated solution methods, the proposed decomposition algorithm allows for the solution of multi-regional and multi-sectoral OLG models that exhibit a large number of heterogeneous consumers and a variety of household-specific effects. By broadening the scope of economic analysis, this new approach provides a powerful tool for applied general equilibrium modelers. In this book, the algorithm is applied to the macroeconomics of demographic change, demonstrating its flexibility and scope as a solution concept. With a specific analysis on the implications of globally unsynchronized demographic patterns for international trade, the book also explores the sectoral and distributional consequences of an aging population in Germany.