Anthony Johnson sets out an interesting and convincing argument as to how Stonehenge was built and the time line for the different phases of its construction. Using analysis of the position of the stones together with the many years of archaeological research, Johnson demonstrates the simple formula that could have been applied to survey and create the monument. It was interesting to see the different approaches to its research over the years and the changes that have occurred to the structure through natural causes or through man-made error. It is clear that this book has been painstakingly researched in order to give a comprehensive and detailed account. Some of the mathematics was slightly over my head but this did not detract from the book which I found a thoroughly interesting read.