This was a big one!  Many viewers figured so much time had passed that the final resolution to this question couldn’t possibly live up to the hype, but it did!   Locke was paralyzed when his father shoved him out of an eighth story window!  Talk about father issues! 

Not only was the story very rewarding, but it was capped with the revelation that Locke's father, Anthony Cooper, had somehow come to the island!  This was an excellent segue into another of LOST’s big reveals.