This book represents a culmination of my Ph.D. research conducted at the Ruhr Graduate School in Economics and at the University of Duisburg-Essen from Oc- ber 2005 to April 2008. Many people have generously contributed their time, ex- rience and resources towards the success of this dissertation. First and foremost, I would like to thank Prof. Dr. Volker Clausen, a great sup- visor, who has always encouraged my work. It has been a pleasure to work under his excellent guidance. His steady engagement and support have provided me the kind of working environment that has proved to be instrumental in writing this thesis. I am also grateful to my second supervisor, Prof. Dr. Thomas F. Rutherford, who has inspired my work from the beginning. This thesis would de?nitely not have been possible without his innumerable and fundamental contributions in the area of c- putational economics. As a co-author of Chapter 2 of this thesis, he was a pleasure to collaborate with and learn from.

Introduction.- Computation of Equilibria in OLG Models with Many Heterogeneous Households.- Trade Liberalization and Global Demographic Change: A Quantitative Assessment.- Quantifying the Sectoral and Distributional Effects of Demographic Change in Germany.- Concluding Remarks.