This book documents and analyses the transformations in the Jewish-owned economy active in Salonica during the period of the consolidating Greek nation-state, prior to World War II. Based on archival materials, the author provides a comprehensive, comparative inter-ethnic empirical study of Jewish entrepreneurial patterns for two distinct historical periods: the multi-ethnic business world of Greek Macedonia (1912-1922) after its incorporation into the Greek nation-state; and the era of minority-majority relations (1923-1940), following a radical modification of the city's demographic composition -- a process that culminated in Salonica's ethnic unification. A macro analysis combines a comparative static overview of the Jewish-owned firms vs. the Greek-owned firms active in the city at three points in time (1912, 1921, 1930), with a dynamic analysis focusing on transitions in structure and entrepreneurial behaviour. A micro analysis then examines the characteristics of Salonica's Jewish entrepreneurial elite, its businessmen and professionals, including class resources, familial and ethnic networks, business strategies and methods. Included in the analysis is a unique database illustrating Jewish entrepreneurial patterns during the 1930s. This study applies the "ethnic economy" approach in explaining Jewish entrepreneurial dynamics, and contributes new theoretical insights. The research presented provides hitherto unavailable details about the economic and demographic history of the Jewish community of Salonica, a city known as the "Jerusalem of the Balkans" due to it being home to the largest concentration of Sephardic Jews found in the territories once belonging to the Ottoman Empire.