Regarding the prologue from ADF's novelization of ANH:
No reference to any other Emperors.. . . Aided and abetted by restless, power-hungry individuals within the government, and the massive organs of commerce, the ambitious Senator Palpatine caused himself to be elected President of the Republic. He promised to reunite the disaffected among the people, and to restore the remembered glory of the Republic.
Once secure in office he declared himself Emperor, shutting himself away from the populace. Soon he was controlled by the very assistants and boot-lickers he had appointed to high office, and the cries of the people for justice did not reach his ears.
Having exterminated through treachery and deception the Jedi Knights, guardians of justice in the galaxy, the Imperial governors and bureaucrats prepared to institute a reign of terror among the disheartened worlds of the galaxy. Many used the Imperial forces and the name of the increasingly isolated Emperor to further their own personal ambitions.
. . . From the First Saga, Journal of the Whills
-- STAR WARS: From the Adventures of Luke Skywalker, New York: Ballantine, 1977; Hardbound Ballantine Books Edition: October 1977. First Edition: December 1976. Page 1.
Yeah, it's later in the book. I never said it was in the prologue.