Thank you for your excellent lessons in astronomy. I particularly enjoyed Measuring Distance in the Universe.

An excellent book on this topic is Measuring the Universe by Stephen Webb. This book covers the various measurement techniques with plain English explanations along with the math.

Another excellent resource is provided by Dr. Wendy Freedman, one of the few astronomers who makes compicated astronomical issues comprehensible, here: http://xxx.lanl.gov/abs/astro-ph/0308418

Eric Bier