The work summarized here is a portfolio dissertation consisting of an introduction, five peer-reviewed articles (Chapters 2-6), and a concluding chapter. Chapter 2 serves to set the stage for later chapters by providing a traditional literature review of our knowledge of the roles of business associations (BAs), with the following key findings: 2.1: The widespread approach which distinguishes between the beneficial, market-supporting, and the harmful, rent-seeking roles of associations is not justified as all of the proposed economic roles of BAs can involve activities linked to the private order and the public order, and all of the economic roles can contribute to both value-creating and redistributive rent-seeking. 2.2: The proposition that a certain institutional strength is needed for a BA to be able to fulfil beneficial “market-supporting” economic roles is not supported by the evidence, as beneficial contributions from each of the economic roles of BAs are possible at each of their levels of institutionalization. 2.3: Socially beneficial or harmful orientations of BA activities are explained by the incentives institutionalized by private-order (market pressures, organizational competition, and internal governance) and public-order (political accountability, monitoring) actors. Chapter 3 seeks to test hypotheses on whether specific groups of professional community institutions – in our case BAs –fulfil a transaction-supporting role, with the following key findings: 3.1: The majority of BAs in our sample institutionalize transaction-supporting functions such as moral and professional selection and control, business dispute resolution, and information sharing. 3.2: BAs are important elements of the institutional framework behind contractual relationships, as several functions of BAs contribute to perceived internal and external trust in business partners. 3.3: BA membership in general does not increase credible commitment among business partners. However, BAs with functions relevant to contract enforcement enable firms to reduce the threat of opportunism with any business partner. 3.4: BA membership does not facilitate the creation of new partnerships with previously unknown or geographically distant partners but might facilitate building trust in them once they are established. Chapter 4 digs deep into the puzzle of how professional communities are institutionalized for a single role, that of enabling market transactions, with the following key findings: 4.1: There is a trade-off between relying on professional community institutions and relying on long-term relational contracting (or integration) for the governance of contractual relations. 4.2: There is a trade-off between relying on professional community institutions and relying on market reputational mechanisms for the governance of contractual relations. 4.3: Reliance on market intermediaries can both complement and substitute for reliance on professional community institutions for the governance of contractual relations. 4.4: The scope and type of government involvement in the governance of contractual relations strongly determine the role of professional community institutions. Chapter 5 zooms in on the factors influencing the development paths and relations between professional associations, looking to clarify alternative theories and their relationships, with the following key findings: 5.1: The theory linking the logic of membership to lower layers and the logic of influence to higher layers of institutionalization has found partial support, while the logic of influence is more significant than theoretically expected in lower institutional layers and early phases of institutionalisation. 5.2: In the later stages of associational development competition for members, the logic of membership and the logic of influence push them to expand their functional and membership domains. Contrary to theoretical expectations, differentiation did not increase over time. 5.3: The logic of influence dominates as expected at the layer of associational integration, but does not lead to ever more extensive coordination. The uncertain and unstable institutionalization of the profession within the government is reflected by community institutionalization. 5.4: Remaining patterns of differentiation are largely explained by differences in the institutionalization of intellectual debates, which proved to be more persistent than functional and membership profiles. The construction of a professional community’s identity and its institutionalisation are parallel, linked processes. Chapter 6 aims to connect the research on political science as a scientific field to the study of professional communities, with the following key findings: 6.1: In terms of membership, the identity of Hungarian political science has become more compact. There is an identifiable and increasingly clear professional community, but the discipline remains open to external contributors. 6.2: The increased international academic output provides visibility for the profession, and the increasing share of quality publications adds to its status and institutional position. 6.3: Publication performance and international recognition are unevenly shared among members of the profession, which could reflect uneven access to resources or a lack of internal connections. The community’s integration into European political science is through the activities of a small group of high-performing professionals in central institutions. 6.4: Understanding the development of newcomer professional communities calls for a combination of performance- and personnel-centred, and institutional perspectives, allowing us to study relations between professional institutionalisation and the development of underlying professional networks.