This paper traces the evolution of the National Assessment of Educational Progress (NAEP) program with an emphasis on the concurrent evolution of NAEP’s primary and secondary purposes. The author divides the discussion into four time periods: 1963-1969 (the gestation period), 1970-1983 (ebb and flow of early NAEP), 1983-2002 (transition to an IRT-based design, creation of the National Assessment Governing Board, and inception of state-level reporting), and 2002- present (modern era). The most detailed treatment is given to the modern era, with the author devoting separate sections to the legislation governing NAEP, the schedule of assessments, the primary reporting mechanism, and the transition to digital assessment.