In recent years, the literature in the field of law and economics has grown rapidly and has attracted interest among some legal philosophers in Japan. However, the majority of jurists and philosophers seem to remain skeptical about the relevance of economics to general jurisprudence and specific areas of law. To explore this relevance, it is necessary to scrutinize the methodology of economics from the philosophical perspective and to examine the multi-faceted relationship between the market and legal institutions. This keynote paper briefly discusses some basic concepts, methodological features, and research topics of law and economics and of economics more generally. To begin with. I consider several fundamental economic concepts, such as efficiency and rationality, by refining the orthodox dichotomy between consequentialism and deontology and by referring to the implications the observations in behavioral economics have for the standard form of law and economics. Next major differences between economic methods and legal ones are identified, and the possibility of integrating the two bodies of methods is explored. Then. I discuss phenomena in interactive relationships between the market and legal institutions, including the paternalistic interferences by the legislature and the court into market transactions and the impacts of general perceptions and expectations among producers and consumers upon policy achievements. This paper concludes by summarizing the succeeding paper presentations and comments on them, each of which focuses on one or another of the topics mentioned above.