Then the pan boils

Decipher this opening line

Then the pan boils

Kqno fp pddpyetlwwj b nluacw djh, qm uc lyzomy rm qxhb gr jhqwysqbbo.

Then the pan boils

and win a prize

Then the pan boils

Identify the book and author

Then the pan boils

and win two

Then the pan boils

If no-one wins by 1 March 2002, a clue will be posted if no-one wins by 1 May 2002, another clue will be posted and so on and so on