I don't have many photography books but the 2 I seem to refer to most often are Basic Photography by Michael Langford
http://www.amazon.co.uk/Basic-Photography-Michael-Langford/dp/0240515927 the Amazon link takes you to a much more recent edition than my copy! Might ask Santa for the latest! Almost like a textbook, so not the easiest book to read but crammed full of useful knowledge. The other is The Digital Photographers Handbook by Tom Ang
http://www.amazon.co.uk/s/ref=nb_sb...her's+handbook&sprefix=tom+ang,stripbooks,412 again, crammed full of useful knowledge but an easier read than Langford's rather dry tome!
If you have a well stocked library, they might have a selection of photography books for you to read - if you find any particularly useful, make a note and keep your eyes out in Charity shops or 2nd hand bookshops. Or Amazon!
There's often a very useful book in a camera's box, although it seems to be on a CD sometimes rather than on paper - the manual. Not so much on what sort of settings to use etc but invaluable when it comes to how to do things with your chosen tool.