We predict that most quasars will show the interstellar K line in high dispersion spectra. The expected range of its equivalent width is 0.025-0.350 Å. A systematic study of the interstellar K in quasars and high latitude stars can yield useful information on the distances of quasars. Because the interstellar material in the halo may be rather inhomogeneous the equivalent-width-distance may be different in different directions. Absorption-line quasars can, of course, have an additional contribution from the circumstellar shell. If the profiles of the K line could be measured with sufficient accuracy, it may be possible to separate the interstellar and circumstellar contributions.
If indeed, it is ultimately confirmed that the total number of quasars is about 200,000, it would be reasonable to expect that some of the quasars may be less than 100 parsecs away. The parallax of a star at a distance of 100 parsecs is 0.010 arcsec. It is quite conceivable than one day it may be possible to measure the parallax of one of the nearest quasars.