This is a useful introduction into the topic of cosmology and how it has developed into a subject separate from astronomy. It is a step above a popular science book and is for the reader who really wants to get their teeth into the science of this subject. It starts with a chapter summarising the development of cosmology as a separate area of study from the observations of Kepler in the 1600s through Einstein to the current models and the findings of the Wilkinson Microwave Anisotropy Probe, which were first released in 2003. The chapter ends with a short discussion on the future of cosmology and which subjects are likely to be investigated more in the future.
The main part of the book is an A‐Z of topics in cosmology, including astronomical features; biographies of key people who have developed our understanding in the area; experiments which have been crucial in developing cosmological awareness; the theories which form our knowledge of cosmology; as well as the ideas and mathematical concepts on which these theories are based and that are used to explain them. It covers both theoretical and observational topics within cosmology and explains the links between the two.
The authors are both well‐respected researchers in the field of cosmology and their in‐depth knowledge of the subject area shows in their detailed, yet understandable, descriptions of what can be quite complex topics. It is an interesting read and would suit people wanting to find out more about the subject, as well as people who wish to refresh or update their knowledge in this area. It is a book to be dipped in and out of, rather than to be read all the way through, and provides an engaging way into this enthralling subject area. The equations seem to have been included with care and should not intimidate people – where they are complex their meaning is explained clearly and the details of the mathematical functions is not necessary to understand the science, although it is there for those who are interested in it. The reader does need to know some of the background to the particle physics that impacts on cosmology to understand fully some of the sections of the book, but to include the whole of particle physics would have doubled the size and would have been outside the book's scope. On the whole, I think they drew the line well between what particle physics was needed and what was not, although there are a couple of ideas which I feel it would have been useful to have included (e.g. an explanation of the spin of particles).
There are lots of cross‐references within the text between different entries. It also includes photographs, equations and diagrams where these can add value to the textual description. Some entries also have a list of further reading – including websites, journal articles and books. The index to the book seems comprehensive, and there is a glossary of technical terms and a list of symbols used. Some of the longer entries are split up into sections and I found it difficult to distinguish these sub‐headings from the headings for a new entry, but this is a minor point in a very impressive book overall.
