The observational determination of astrophysical parameters of horizontal-branch A stars is discussed. Effective temperatures, surface gravities, and bolometric magnitudes are determined for seven field horizontal-branch A stars, and their masses are calculated. The mean mass for these seven stars is 0.6 + or - 0.4 solar mass. This value is in excellent agreement with evolutionary tracks, but the uncertainty is so large that the close agreement is largely fortuitous. The helium abundance of globular cluster stars is discussed, a value of Y = 0.25 is adopted. This result is in good agreement with other determinations. The measurements used have important weaknesses. Those places where the observations or their interpretation need to be improved are identified. The improvements can be made with present hardware and software, and promise to result in critical tests of evolutionary theory.