In November 1977, Ballentine put out this 75 page Star Wars Album featuring tons of color and black and white photos from the movie and behind the scenes shots. The contents seems to fall into three sections, this first of which is a look at the influences on the movie. Everything from early sci-fi like H. G. Wells to Flash Gordon, robots in movies (i.e. Metropolis and Forbidden Planet), comedy duos like Laurel and Hardy, westerns that influenced the character of Han Solo and the whole cantina scene, monster movies and Errol Flynn swashbucklers are referenced. I like this bit as it's easy to think of Star Wars as its own entity nowadays rather than the throwback to old fashioned adventure serials it was originally intended to be.
The second section is a breakdown of the movie's plot accompanied by many pictures.
The final part of the book is devoted to behind the scenes stuff with articles, pictures and concept art.