Literature from several phases of the career of Masahisa Fujita is surveyed chronologically, with a view toward future contributions in these areas. First we address the economic structure of the interior of a city with mobile consumers, adding production. Next we provide a critical discussion of the new economic geography, in particular distinguishing between recent approaches employing two regions and more than two regions, both in theory and in application to data. Finally, we discuss knowledge creation in groups and briefly touch on his current work in artificial intelligence.