The Iron Grail, by Robert Holdstock—
....where Holdstock scores best is in stressing not Merlin's Disneyesque humanity but his very otherness. This Merlin stands apart from the brief, furious lives of those around him: a shabby figure of power as old as the local gods and undoubtedly more terrifying, if only he'd stop hoarding his magic like a miser. This is fantasy at its most intelligent and most demanding.

Jon Courtenay Grimwood's review in UKGuardian