In 1997 the International Federation of Library Associations and Institutions (IFLA) initiated a project to promote and defend the right to information. This decision to engage proactively with human rights was a radical expansion of the profession's self-conception. Applying an action research methodology, this study traces the development and implementation of the Free Access to Information and Freedom of Expression (FAIFE) initiative. It traces the origins of the decision, and assesses the outcomes of its first five years as it developed from a project into a continuing and central program of the Federation. Both the internal effects on IFLA and the consequences of the project for the profession of librarianship are explored. The thesis locates the key decision in the history of librarianship, its growth as a profession paralleling the development of libraries as institutions. In turn, the decision is also located in IFLA's own history, and the way it survived and worked to advance the ideas and tools of librarianship amid difficult and changing international environments. The politics of professionalism is at the core of the study. The disturbing innovation which FAIFE represented took IFLA outside its traditional focus on the status and techniques of the profession, postulating a new role for the Federation. By investing librarianship with a higher responsibility, it has gone further than the now widely accepted expectation that professionals will place community interests before organisational and personal interests at all times. The responsibility to promote the fundamental human right to information has been embraced as the key principle underlying and informing library and information service, the touchstone for evaluating professional priorities. This locates the primary purpose of the profession outside the profession's institutional base in a supranational, absolute and almost universally recognised social goal. Adopting these aspirations and this role carried many dangers for IFLA. It would inevitably seem a deviation into politics by some. It heightened the risks of both internal dissent and external criticism. It challenged the habitus of disinterested professionalism by invoking a more interventionist social responsibility for IFLA, its constituent library associations and the broader profession. It drew on evolving and contested understandings of professional responsibilities in a complex global environment and has redrawn the accepted boundaries of professional discourse in librarianship. At least so far, the consequences have been beneficial for IFLA, reinforcing its jurisdiction and strengthening the Federation. As an international federation of professional associations, IFLA faces particular challenges in working across diverse national traditions, ideologies and cultures. Its existence and effectiveness rest primarily on internal cohesiveness. Its capacity to develop the FAIFE initiative into a program without schism, and indeed with growing support, has strengthened rather than weakened its organisational capacities. Through that process IFLA has reinvented itself, to a considerable degree, as a form of transnational social movement organisation. It has developed strong relationships with other civil society organisations while maintaining its position as a respected international professional body. It has strengthened its position by becoming a vigorous advocate for the right to information, thereby becoming an actor in the growing international concern with human rights. This study of a decisive period in IFLA's history offers a rare example of an international professional association in transition. In examining this project to promote unrestricted access to information as the reciprocal right of freedom of expression, the research is a case study of the politics of an expanding sense of professionalism. IFLA's experience is pertinent to a range of other organisations, and is itself part of the realignment of international political discourse in response to the growing influence of international organisations and the priority of human rights in international political agendas.