This study intends to make a comprehensive inquiry into the meaning and limitations of Discovery, and to explore how to make full use of Discovery in library cataloging. To this end, first discussed is the meaning of Discovery, which has a variety definitions. For the quality evaluation, 5 criteria were developed on the basis of literature review. Then this study conducted the quality evaluation on the basis of previously developed 5 criteria and usefulness of Discovery in library catalogs is thoroughly discussed. Based on these, the final discussion includes strategies for Korean LIS scholars and library practitioners to consider when applying Discovery as an integrated search tool.