I investigate how social networks affect processes and outcomes in organizations and markets, with special attention to labor markets. To this end, I treat social networks as 1) tools that can be used by organizations, managers and job-seekers to contend with uncertainty, and 2) objects of study regarding how they develop in the workplace due to the external (labor) markets in which organizations are situated. I study organizational practices related to social networks (e.g. network-based hiring) and “alternatives-to-networks” practices (e.g. tryouts), and the near and more distant consequences of these practices on employees and organizations, including the effects of these practices on the social and economic outcomes of members of different socio-demographic groups.