The book starts with a chapter on plate tectonics to explain why it is that we have volcanoes and earthquakes. The next 6 chapters are about volcanoes, then 2 chapters on earthquakes and one on tsunamis. I wondered at first if this was due to the author's bias (David Rothery is a vulcanologist with the Open University), but to be fair there is a lot more to say about volcanoes.

The chapters on earthquakes look at how and why they happen and how the risks can be minimised. Similar material is covered with respect to tsunamis.

Although I knew quite a bit of the material in the book before I started, there were nuggets included that I didn't know, and the whole made a useful summary for me. It is written at a level suitable for an interested non-geologist. It is also readable, with technical jargon used only where necessary (although it is often necessary), and explained when it is first used and in a glossary in the back of the book.

So if you have ever wanted to know more about volcanoes, this is a great place to start.