Short answers, pulled from the story.
Alan Dean Foster wrote the 1976 novel Star Wars: From the Adventures of Luke Skywalker. George Lucas decided that his own name should appear on the cover instead of Foster's name.
Ballantine Books released the paperback version of Star Wars: From the Adventures of Luke Skywalker on the 12th of November 1976. The initial print run consisted of half a million copies which sold out by February 1977.
Jabba the Hutt is described as a fat biped with a shaggy skull and jowels shaking when he moves in the book. He bears scars marking his ferocious reputation in combat unlike the giant slug creature shown later in Return of the Jedi.
The novel opens with Another galaxy another time instead of the famous crawl used in the film. The prologue titled From the First Saga: Journal of the Whills describes Senator Palpatine causing himself to be elected President of the Republic before declaring himself Emperor.
George Lucas wanted the book to carry his own name as the author so the film would feel more cohesive when audiences encountered the story in print form. Foster accepted the role without hesitation or complaint about the lack of public recognition.