I've just returned from a one-week tour of Iceland following mostly the ring road, with this book as my constant companion. If you are at all interested in geology (and if you are going to Iceland, you should be!) get this book. Even if you have no background in geology, the excellent introduction will get you somewhat up to speed on plate tectonics, vulcanism, glaciation and climate cycles of the past 16 million years (age of oldest rocks on Iceland). Each subsequent chapter presents a part of the country, concentrating on easily-accessible locations as much as possible (of course, some outstanding features are by definition inaccessible). There are chapters on Reykjavik, the Reykjanes peninsula, the Golden Circle (geysir, Thingvellir etc.) which you can easily reach even if you are on a short break in the Reykjavik area.
But... to make full use of the book you must purchase the excellent 1:250000 topographic maps of Iceland issued by the survey; you will find these at most newstands and gas stations once you get to Iceland.
Iceland is a wonderful place to visit and after reading this book you will admire the Icelandic spirit which perseveres in spite of living with the constant threat of catastrophic events. And if you want to see glaciers in action, this is the place to be.