This review updates the 1969 Particle Data Group review of particle properties, providing evaluated data, averages, and summaries in tables and wallet sheets. The text outlines the procedures for data retrieval, selection, and analysis, including criteria for identifying resonances and handling inconsistent data. It discusses statistical methods, error analysis, and the treatment of data from various experiments. The review includes detailed tables for stable particles, mesons, and baryons, along with notes on their quantum numbers, decay parameters, and other properties. The text also addresses the interpretation of experimental results, the role of symmetry principles, and the implications of CP violation in K decays. It covers the analysis of muon decay, the determination of form factors in K leptonic decays, and the study of baryon decay parameters. The review emphasizes the importance of consistent data processing, the use of weighted averages, and the application of statistical methods to ensure the reliability of particle property data. The text also includes a detailed explanation of the data card listings, the use of wallet sheets and data booklets, and the procedures for handling and interpreting experimental results. The review concludes with acknowledgments of the contributions of various researchers and a bibliography of relevant references.This review updates the 1969 Particle Data Group review of particle properties, providing evaluated data, averages, and summaries in tables and wallet sheets. The text outlines the procedures for data retrieval, selection, and analysis, including criteria for identifying resonances and handling inconsistent data. It discusses statistical methods, error analysis, and the treatment of data from various experiments. The review includes detailed tables for stable particles, mesons, and baryons, along with notes on their quantum numbers, decay parameters, and other properties. The text also addresses the interpretation of experimental results, the role of symmetry principles, and the implications of CP violation in K decays. It covers the analysis of muon decay, the determination of form factors in K leptonic decays, and the study of baryon decay parameters. The review emphasizes the importance of consistent data processing, the use of weighted averages, and the application of statistical methods to ensure the reliability of particle property data. The text also includes a detailed explanation of the data card listings, the use of wallet sheets and data booklets, and the procedures for handling and interpreting experimental results. The review concludes with acknowledgments of the contributions of various researchers and a bibliography of relevant references.