The book is divided by time period, a short historical overview in chapters dedicated to Mesolithic, Neolithic, Bronze and Iron Age Orkney followed by the Picts, Norse and Earl eras and then 18th, 19th and contemporary history. The book covers a lot because there's a lot to see in Orkney, a place where recent history is often closely linked to ancient eras. It also means that there is a constantly stream of new things to examine in the islands, so the book benefits from a new chapter on "recent archaeological discoveries", which includes, among other things, Norse burial sites in Papa Westray and the hugely important Ness of Brodgar.
On occasion I found the book a little too compartmentalised. The fantastic Neolithic tomb of Maeshowe is described in detail, and Wickham-Jones mentions the Viking graffiti in it, but doesn't offer translations or information until the section on Norse history. A casual reader using the book as a guide book might easily miss these links. I was also surprised to see little or no discussion of enclosure, displacement or clearances relating to the sites mentioned or the history of Orkney. Given the role this played in the transformation of Orkney's farming landscape I was surprised by this.
Nonetheless this is an extremely useful book that every visitor to the islands ought to read as an introduction to the history and landscape of Orkney.