Thermodynamic properties of pyridine (Chemical Abstracts registry number 110-86-1) are reviewed, and detailed comparisons between literature values and new recommended values of this research are provided. Properties reviewed are condensed- and gas-phase molar heat capacities, the molar enthalpy of combustion, vapor pressures, densities, critical properties, virial coefficients, molar enthalpies of vaporization, and molar thermodynamic properties derived from assigned vibrational spectra. In a companion paper to this review, new vapor pressures, high-temperature molar heat capacities, and densities are reported which show that previously assessed values for pyridine require revision. Recommendations are made for values of all properties reviewed. Thermodynamic consistency between properties is emphasized.