The best golf book I've read by miles, and I've read a few, is 'In search of Tiger'. Next best would be '4 iron in the soul', cant remember the authors.
I wouldn't take on any golfing advice from Darren Clarke, he doesn't have a winners mentality just tons of power, doesn't practice, drinks and smokes too much etc.
I read 'seven laws of the golf swing' by Nick Bradley recently, who is hanging onto Justin Rose's limited success, but it was a bit too new worldly for me.
Ben Hogan's old book on the swing is a good reference, any man of 135 lbs who could hit a ball like he did deserves respec...Aye