[Spoiler alert!]
I just finished Pale Fire, and am really enjoying turning it over in my mind. It ends up being about the relationship between a poet and a madman, laying their two creations side by side. The poet was by far the kinder and more human of the two, and in fact his tolerance of the poesis of madness accounts for the remarkable kindness shown to his eccentric neighbor.
It is clear that the author of the second portion is a lunatic, (probably paranoid schizophrenic, as he is overly cautious in unreasonable ways while being reckless in reasonable things, hears voices, and has fits of hysterical grief), but what was not immediately clear was whether he was also royal. I couldn't understand why the killer waited for the poet at the madman's door, but just remembered that it was the madman's rented door, rented from a judge on sabbatical whose appearance at dusk was probably very similar to the poet's.