Bass Guitar for Dummies is good, if rather American in style - not really to my taste.
The Bass Handbook by Adrian Ashton is also good, [url="http://www.amazon.co.uk/The-Bass-Handbook-Complete-Mastering/dp/0879308729/ref=sr_1_1?s=books&ie=UTF8&qid=1339008473&sr=1-1"]http://www.amazon.co...39008473&sr=1-1 [/url]
It covers much the same stuff, but I prefer it.