"Astronomers are making tremendous progress in establishing the distance scale of the universe. For the present, however, we often are happy to use the relative distance scale, simply giving the observed redshift of a galaxy or quasar and allowing efforts to translate redshifts into absolute distances in light-years (or kilometers, or whatever) to be part of a controversy that is fun to watch."
Pasachoff suggests that interested readers might want to check out the following references:
Astronomy: From the Earth to the Universe, by Jay M. Pasachoff. Fourth edition. Saunders College Publishing, 1995.
The Farthest Things in the Universe, by Jay M. Pasachoff, Hyron Spinrad, Patrick Osmer and E. S. Cheng. Cambridge University Press, 1994