Gene Wolfe

Gene Wolfe is a reputable engineer who helped design the special oven that Pringles are baked in (or something - see wikipedia for the exact fact).  He is also the author of some of the most profound fantasy and sci-fi.  Ursula  Le Guin is often quoted on his book jackets saying 'He is our Melville' and she's right.  The theological riches in his best books are amazing. If you haven't read any, I recommend you don't start with the Book of the New Sun - it is a magnificent series, but it is hard to get it all first time through. Re-reading is almost essential.

In addition to the usual sci-fi strangeness, Wolfe very often works through a memoirist, who may liken things to events which are yet to happen in the narration, and often an unreliable memoirist.

The Fifth Head of Cerberus is brief enough and representative enough to be a good starting place for those who are patient with literary novels. Alternatively Soldier of the Mist is a good starting place for someone who usually reads fantasy.  The Wizard-Knight (two books, The Knight and The Wizard) is Wolfe putting his own spin on the western fantasy world, with a fully worked out cosmology of seven realms from the heaven of the Most High God, to the hell of the Most Low God, and the hero, Sir Able of the High Heart, is like Axecop in armour.  There is even a thread back to our own world and what Sir Able achieves for us from his world.

Wolfe's faults.  Sometimes the narrators are so unreliable that you wonder if GW is really in control.  Sometimes the story structure is just confusing or under-developed around a great world.  Free Live Free is extraordinary in some ways, but I'm not racing to re-read it, because the meat of the story is the repetitiveness of the faults of the characters. Castleview seemed like just a mess to me. The Book of the Long Sun seems to end with a whimper, although its continuation in another series may resolve all that.

For all that, Gene Wolfe is the only fiction author that has reconfigurative power for me, who re-orders my thoughts, who sows reality with latent epiphanies which land when you read other books, or in conversation, or in deep thought. I will read a bad book of his before a good book of someone competent but predictable like Iain M Banks.