This special edition of IJMSE focuses on the Programme of International Student Assessment (PISA) project now that it has completed a full cycle of administration--reading, mathematics, and science--to look at ways in which PISA has been used in participating countries and with what consequences, and to identify potential research and policy directions emanating from this initiative. Articles were invited to (a) reflect international perspectives on the uses and consequences of PISA to date and (b) speculate on future directions for research, curriculum, and policy using the PISA datasets. The introductory article provides a brief overview of common aspects of PISA: Evolving definitions of reading literacy, mathematics literacy, and science literacy; technical design of the instruments and data analysis procedures; the changing emphasis of administrations; and recent research using the datasets. PISA, unlike other international assessments in reading, mathematics, and science, has provided a fresh perspective on "what might be" by decoupling the assessment from mandated curricula to focus on literacies needed for a 21st century economy. This unique feature of PISA brings with it possibilities and cautions for policy makers.