Paul Meehl's contributions to methodology and the philosophy of science extend well beyond his widely known writings in such areas as construct validity and statistical significance testing. I describe one of Meehl's less well-known, but potentially most important, methodological undertakings: his work on metascience, or the science of science. Metascience could ultimately revolutionize our conceptualizations and understanding of science and provide considerable help to practicing scientists and scientific endeavors, including efforts to advance the development and appraisal of theories in psychology.