Lord Foul's Bane is a fantasy classic that I have read before; twice, I believe. But it was so long ago, that I have been meaning to re-read it for awhile.  The books I have are so old, Amazon doesn't even have the images to link in.  Hopefully Wikipedia doesn't mind.

Lord Foul's Bane is the beginning of the story of Thomas Covenant called Unbeliever.  He is a modern day man afflicted by Leprosy.  He finds himself unwillingly thrust into The Land, a mystical realm that is able to resolve some of his nerve damage and remove his disease.  But he is wary, knowing it must be too good to be true.  He must deliver a message of Doom to the leaders of the Land, and resolve his inner turmoil of even being there.

Covenant is a reluctant hero with fears and flaws that match our own.  Donaldson's treatment of him is very deep and extremely satisfying when looking for a character that is more realistically complex.  He spends much of this book battling the psyche of the main character himself.  There are others, I am certain, that have written this series up far better than I.  For more, find such a review online.  This is the first book of the first trilogy of the Chronicles of the Unbeliever.  The 2 trilogies were so popular that Donaldson has started the 3rd and final a couple years ago.  The Chronicles of Thomas Covenant are, without a doubt, required reading for any fantasy fan.