Historically, the primary governance of the Internet has been in the hands of the Internet Corporation for Assigned Names and Numbers (ICANN), a non-profit corporation appointed by the US government to develop policy for and manage the critical resources of the Internet: Internet Protocol addresses, Domain Names System and parameter numbers. However, because of the immense global influence of the Internet, other national governments and international organizations are seeking to rapidly become involved in this policy-development sphere. In this particularly decisive moment of the Internet, there is a need to understand the structure and processes of ICANN before any further change. This paper studies who participates in ICANN’s decision-making and policy-development processes and how. It first examines in detail the internal structure of the organization, and then its structural and financial evolution since its inception. The study is an in-depth analysis of legal, financial and public documents of ICANN, as well as the information published directly by ICANN’s internal bodies. Although other works have studied specific internal bodies of ICANN, this is the first comprehensive examination of ICANN using ICANN’s founding documents as starting point. The paper reveals the substantial expansion in scale and scope of ICANN’s initial technical mandate. ICANN’s recurring changes allowed it to adapt to growth, evolution and change in the Internet However, the permanent restructuring hinders follow-up by external interested parties that are now requesting more involvement in the policy- development processes.