Since its creation in 1980, the Office of Information and Regulatory Affairs (OIRA), a part of the Office of Management and Budget (OMB), has become a well-established institution within the Executive Office of the President. This essay, based on public documents and the author’s experience as OIRA Administrator from 2009-2012, attempts to correct some pervasive misunderstandings and to describe OIRA’s actual role. Perhaps above all, OIRA operates as an information-aggregator. One of OIRA’s chief functions is to collect widely dispersed information – information that is held by those within the Executive Office of the President, relevant agencies and departments, state and local governments, and the public as a whole. Costs and benefits are important, and OIRA does focus on them (as do others within the Executive Branch, particularly the National Economic Council and the Council of Economic Advisers), above all in the case of economically significant rules. But for most rules, the analysis of costs and benefits is not the dominant issue in the OIRA process. Much of OIRA’s day-to-day work is devoted to helping agencies to work through interagency concerns, promoting the receipt of public comments on a wide range of issues and options (for proposed rules), ensuring discussion and consideration of relevant alternatives, promoting consideration of public comments (for final rules), and helping to ensure resolution of questions of law, including questions of administrative procedure, by engaging relevant lawyers in the executive branch. OIRA seeks to operate as a guardian of a well-functioning administrative process, and much of what it does is closely connected to that role.