I might have to disagree slightly with Mike's recommendation here... Cappa is a great picture book with plenty of gorgeous items illustrated, but a surprising proportion of the attributions are questionable, especially for the less well known/ well documented makers. For example in the Sevres section, specifically pp.421-2, I see glass by Consolidated, Inwald and August Walther, all wrongly attributed to Sevres with no explanation why and no references given. There are also many other attributions throughout the book which others have called into question, especially for older, unsigned pieces (though I don't have enough knowledge in this area to confirm if they are correct or not), and there are some quite speculative entries like that for Verlux.
While no book which offers such a broad overview is likely to be entirely error-free, it's the rationale underlying the attributions which worries me; for example on what basis did the author decide a Walther float bowl was by Sevres when it is unmarked and undocumented?
On the plus side, however, there are a great number of nicely illustrated examples by the acknowledged masters of French glassmaking and it is a very enjoyable book and not prohibitively expensive (I paid around £50.00 GBP for my copy). So, on the whole I'd recommend it, but don't rely on it as a sole source for attributing a piece, especially if it is unsigned!

Steven