ESDU 79030 gives vapor pressure data for 40 compounds, in the form of tables. The vapor pressures have been critically evaluated and their temperature variation fitted by an equation in the form of a series of Chebyshev polynomials. The constants of the Chebyshev equation for each compound are given, together with the constants of the approximately equivalent Wagner equation. Also tabulated are values of critical temperature, critical pressure and acentric factor. Tables of temperature at selected vapor pressures and tables of vapor pressure at 5 K intervals are given for pressures from 0. 00001 atmospheres to the critical point.