The overriding message from most current research on computer-based technology in K-12 education is that technology is a means, not an end; a tool for achieving goals, not a goal in itself. Yet many schools and districts make their investments before establishing clear plans for technology use. The real question is not whether technology can make a difference in instruction and learning, but how and under what circumstances it does. This brief examines that question. It reports on key research findings, setting aside decisions about hardware and software purchases in favor of focusing on larger policy and pedagogical issues. It then summarizes lessons learned about conditions for effective technology use. Finally, it explores policy implications. (Contains 16 references.) (AEF)