A bit more general but still relevant, can anyone recommend decent guidebooks to Spain?

Lonely Planet and Rough Guides aside are there any other guidebooks that cover Spain particularly well?
I discovered a few years back that Routard and Michelin were particularly good for France and the Low Countries and was wondering if there was anything else out there that gave a good coverage of Spain?

Unfortunately my languages are not up to much so I am pretty much limited to English, as details in other languages would be lost on me.

More specifically can any one suggest a good resource for Salamanca?

Unfortunately I cannot help you on Salamanca (wonderful city that you will certainly like, also because of the pleasant student atmosphere), but some general guidebook tips:
- The Michelin Green Guide also is good for Italy. There's one for Spain too but I haven't used that one and it gets mixed reviews on Amazon.
- For Toledo there's a great guide called "Toledo. The Magic of Three Cultures" (published by Límite Visual and available in Toledo itself). It's part of a series that also includes Lisbon and Santiago de Compostela. Over 400 pages on one city! With photos, stories and maps. Looks a bit like the Eyewitness Travel Guides series (which I like in general for European cities).

I suggest you use this site for opening times and admission prices if you are planning to visit world heritage sites in Spain: http://www.spain.info/TourSpain/Arte+y+Cultura/Patrimonio+de+la+humanidad/?Language=e n

It's the official tourist site for Spain and helped me last summer when I was visiting Spain. It is much more accurate and updated than most guides.