Lord Foul's Bane The IllEarth War The Power that Preserves
The Second Chronicles of Thomas Covenant, which includes:
The Wounded Land The One Tree White Gold Wielder
and recently SRD started the Last Chronicles of Thomas Covenant which consists of
The Runes Of The Earth The Fatal Revenant Against All Things Ending(TBR) The Last Dark(TBR)
The books follow the story of Thomas Covenant and his adventures in the mystical realm called "The Land". Thomas Covenant is a writer who contracts leprosy. The progress of the disease is arrested, but Covenant is shunned by the society around him. Embittered and with a deepening sense of cynicism, Covenant is transported to "The Land", a world whose basic, accepted realities prove to be an assault on everything Covenant knew to be true.
What makes this series so fucking awesome is the underlying psychology of the story. Any good series has an allegorical component to it. That's what makes a series relatable to so many people. With most epic fantasy series, though, the allegory is on a societal level. Things like whether or not societal progress can be halted and reversed, or whether the pursuit of scientific advancement is detrimental to a society. With the Chronicles of Thomas Covenant, the underlying allegory has to do with ONE PERSON.
And what's better is that the person whose psyche the author chose to explore is NOT a nice person. Due to years of enforced isolation due to the stigma attached to his disease, Covenant is (to a certain degree) mentally unbalanced. Add to the mix a healthy dose of self-hatred, anger, depression, a tendency to bottle up emotions, a loss of the sense of touch, and a sense of self-preservation honed to a nearly obsessive compulsive edge and you have a dangerous, dark persona to deal with. This doesn't make him necessarily evil, but it does make him a loose cannon and unpredictable.
A sentiment which is echoed, ironically enough, in the events of the First & Second Chronicles. (I'm still reading the Last Chronicles, so I can't say that it applies there, but its a VERY strong theme there as well.) Upon his arrival in the Land, Covenant is branded the re-incarnation of the hero Berek Half-hand, whose appearance will either "save or damn the Land" which essentially translates to saving or damning himself, given the similarities in the issues afflicting the Land and those affecting Covenant himself.
The events that occur in the Land mirror Covenant's internal psychological struggles with his self-hatred, his leprosy, loneliness, and despair. And as he has struggled to maintain a balance between himself and the disease in the world, he must now struggle to maintain a balance between the traits that allow him to survive in the world and the changes he has to make in order to survive in the Land.
This series of books, more than any other I've EVER read, truly reflects the awesome power within a single individual mind and the terrible consequences that can come from using that power AT ALL, let alone irresponsibly.
While this series holds a special place in my heart for reasons I won't go into here, I ended up not recommending this to the person who asked for my recommendation. Frankly, this isn't a series to be read when you're in a good mood. Covenant, to me, represents the quintessential anti-hero. But, I love this series and I'm eagerly awaiting the third book in the Last Chronicles. If you want to read this series, you'll definitely enjoy it, just know. The Land isn't Hogwarts, and Voldemort ain't got crap on Lord Foul The Despiser, or for that matter, on Thomas Covenant, the Unbeliever.