It seems the world stood in awe as colourized pictures of the newly fixed Hubble Space Telecope were made public. Since then our knowledge of the universe -- thanks to Hubble, satellite-based devices and other instrumentation -- grows at an accelerating pace. Most recent advances in cosomology often circulate first among scientists and appear in technical journals. Lay news is reported in the popular media, but it is by its very nature piece meal. Therefore, I was pleased to find Clark's newly released, 2nd edition of "Towards the Edge of the Universe". Tantalized by earlier books, I was eager to find an update on recent advances in our understanding of the universe in summary form. This 2nd edition includes new chapters on the architecture of matter and the large scale structure of the universe. Information on the expansion of universe and the formation of galxies has been broadened to include new discoveries. I am not an astrophysicist and cannot evaluate how comprehensive or thorough Clark is in his review. Such judgement is better left perhaps to his peers.
This is not a beginner's book. If you are first coming to the field with a general interest, you would be better served by easy to read books such as "Gems of Hubble" or "Origins: Our Place in Hubble's Universe" --both with spectacular Hubble photographs. "Close Encounters" is geared toward high school students. "Hubble Revisited" is a meatier introductory book.
Clark's book is technical. If you have a college major in physics, chemistry and/or astrophysics (or just enjoyed these college courses), you should be able to understand this book, although it might be challenging for some readers. If you've read James B. Kaler's books, "Cosmic Clouds" and "Stars", Clark's book should be comprehensible, although sometimes more technical in places.
If you are an amateur astronomer and can understand, for example, Sky and Telescope's more techinical articles with ease, you'll find Clark's book probably readable, but very definitely more technical. For the math-phobic, do not be turned away by the apparent liberal sprinkling of mathematical formuals. Everything is explained in English, before the technical formulas are presented.
I personally enjoyed Clark's book and welcomed it into my library. For myself, I am well grounded in scientific research in an unrelated field. Reading Clark's book, I spent little time on most math formuals, had to re-read some sentences, and skipped over some of the very intricate discussions of details, because Clark could make the overall picture clear.