"Accurate thermophysical properties of hydrogen are needed for engineering system design and analysis to support the proposed hydrogen economy. The future use of hydrogen for transportation systems provides some technology challenges. The temperatures and pressures of the systems used to generate and store hydrogen may be beyond the ranges of the currently accepted thermodynamic and transport property formulations developed in the 1980s. We have included a brief discussion of the practical aspects of hydrogen chemistry associated with the storage of hydrogen under various conditions. The nature of normal hydrogen as a mixture of orthohydrogen and parahydrogen is discussed in relation to its behavior. We have surveyed the literature for papers containing experimental data on hydrogen properties and have compiled listings of the available data with ranges of temperature and pressure. In addition, we have presented graphs of the pressure-density-temperature (P-[rho]-T) surface illustrating the available data on both P-[rho] and P-T coordinates. This report includes graphical comparisons of calculated thermodynamic and transport properties of normal hydrogen and parahydrogen with the available experimental data to illustrate the accuracy of the current standard formulations. It also presents graphical illustrations of selected calculated properties using the current standard modes."--Page iii.