Orkney and Shetland Islands by Alan Murphy is one of the Footprint Focus series of guides that, as the series name suggests, focus in on particular areas. As the back cover says, the result is a book which provides you with all the information you need and none of the stuff that you don't.
Essentially, "Orkney and Shetland Islands" comprises the Orkney and Shetland chapters of the Scotland Highlands & Islands Footprint Handbook by Alan Murphy, published in April 2010. The idea is quite a good one. You may be thinking about a trip to the Highlands and Islands more generally, in which case you need the full guide: but if you are specifically planning to go to Orkney or Shetland or both, then why bother to carry around even the most compact and skilfully packaged guide to a much larger part of the country? The result is a slim volume, even when printed on more substantial paper than its larger sibling, which easily fits in the pocket. Easy portability is important in a guidebook: you can't refer to it while out and about if you've left it where you are staying in order to save weight.
The book starts with a chapter on planning your trip, which covers topics such as travel, accommodation and food; plus essential info such as health, banks and visas. This is followed by chapters covering Orkney, and Shetland. Each of these has its own introduction, a map of the archipelago, sections on settlements (including maps of the largest) and individual islands, and listings of places to stay, eat and visit, plus things to do. You end up with pretty much everything you really need to know, in a very compact format. The book concludes with a glossary of Scots and Gaelic terms, though the latter may not be strictly necessary in a book about islands where Gaelic has never been spoken, so does not feature in place names.