This article presents Information Infrastructure Studies, a research area that takes up some core issues in digital information and organization research. Infrastructure Studies simultaneously addresses the technical, social, and organizational aspects of the development, usage, and maintenance of infrastructures in local communities as well as global arenas. While infrastructure is understood as a broad category referring to a variety of pervasive, enabling network resources such as railroad lines, plumbing and pipes, electrical power plants and wires, this article focuses on information infrastructure, such as computational services and help desks, or federating activities such as scientific data repositories and archives spanning the multiple disciplines needed to address such issues as climate warming and the biodiversity crisis. These are elements associated with the internet and, frequently today, associated with cyberinfrastructure or e-science endeavors. We argue that a theoretical understanding of infrastructure provides the context for needed dialogue between design, use, and sustainability of internet-based infrastructure services. This article outlines a research area and outlines overarching themes of Infrastructure Studies. Part one of the paper presents definitions for infrastructure and cyberinfrastructure, reviewing salient previous work. Part two portrays key ideas from infrastructure studies (knowledge work, social and political values, new forms of sociality, etc.). In closing, the character of the field today is considered. [ABSTRACT FROM AUTHOR]