Taking the opportunity, I quote from an uncollected and for this reason
little known Nabokov interview which might be of interest also in other
respects when discussing 'Pale Fire':

"I think it is a perfectly straightforward novel. The clearest
revelation of
personality is to be found in the creative work in which a given
individual
indulges. Here the poet is revealed by his poetry; the commentator by
his
commentary. ['Pale Fire'] is jollier than the other [novels], and it is
full
of plums that I keep hoping somebody will find. For instance, the nasty
commentator is not an ex-King of Zembla nor is he professor Kinbote. He
is
professor Botkin, or Botkine, a Russian and a madman. His commentary has
a
number of notes dealing with entomology, ornithology, and botany. The
reviewers have said that I worked my favorite subjects into this novel.
What
they have not discovered is that Botkin knows nothing about them, and
all
his notes are frightfully erroneous.... No one has noted that my
commentator
committed suicide before completing the index to the book.... The last
entry
has no numbered reference.... And even Mary McCarthy, who has discovered

more of the books than most of its critics, had some difficulty in
locating
the source of its title, and made the mistake of searching for it in
Shakespeare's 'The Tempest.' It is from 'Timon of Athens.' The moon's an

arrant thief, she snatches her he pale fire from the sun. I hope that
pointing out these things will perhaps help the reader to enjoy my novel

better." ('The New York Herald Tribune,' American edition, 17 June 1962,

p.5, interviewer Maurice Dolbier.)