Unlike the previous reviewer I found this book extremely helpful. I went to Lanzarote and I didn't want anything as in depth as Lonely Planet, just something to point me in the right direction. We saw practically all the recommended attractions and were really pleased we did. And if you stick to the recommended restaurants then you can't fail to have a fabulous meal. The only time we tried somewhere not in the book we regretted it!
Having said this, I sympathise with the previous reviewer because the majority of the book was about Lanzarote. The info on Fuertaventura was minimal. However maybe this reflects the number of attractions on Lanzarote in comparison with Fuerta!!