Until recently, researchers in economics and finance paid relatively little attention to household portfolios. Reasons included the tendency of most households to hold simple portfolios, the inability of the dominant asset pricing models to account for household portfolio incompleteness, and the lack of detailed databases on household portfolios in many countries until the late 1980s or 1990s. Now, however, the analysis of household portfolios is emerging as a field of vigorous study. The eleven chapters in this collection provide an overview of current theoretical knowledge about the structure of household portfolios and compare predictions with empirical findings. The book describes the state-of-the-art tools of analytical, computational, and econometric investigation, as well as some of the key policy questions. It provides an original comparative analysis of household portfolios in countries for which detailed household-level data are available (the United States, the United Kingdom, Italy, Germany, and the Netherlands). Finally, it uses microdata for an in-depth study of the portfolio composition of population groups of special policy interest, such as the young, the elderly, and the rich.