I'm planning to walk over the Pyrenees from Catalonia to the Midi this summer, and was looking for a good resource to give me a well-informed idea of possible starting points, finishes, distances and the natural obstacles involved.Although the Rough Guide was slagged off somewhat by previous reviewers for being a) too big to be properly useful as a hiking guide, and b) too useful specifically for hikers (there's no pleasing some people!), I'm glad to say that it's perfect for me - I'm not going to take it on the trip, but I'll be siphoning every little bit of information from it while planning.
And there's a lot of information. For instance, all the telephone numbers for refuges are there - indispensable if you're planning to use them, because you have to book ahead of time.
The guide is divided into chapters according to the valleys specific region of the Pyrenees - this allows you to get straight to only those parts which you're going to walk or visit. And like all Rough Guides, the general knowledge (history, wildlife, etc.) sections really add some colour to the subject.
In summary, I am definitely going to take the Trailblazer "Trekking in the Pyrenees" book with me - it's lighter, smaller, more specific and seems comprehensive - but this Rough Guide was an invaluable starting point.