In 1979, Ballantine Books (then the sole licensed publisher of Star Wars novels and most tie-ins) published two versions of this book. One was a limited edition hardcover, which I have never seen, the other was one of those "trade paperback" editions (coffee table size but in softcover). What made this book a must-get was that it contained the entire fourth revised draft of the screenplay for A New Hope (it was the first time I had seen the Episode IV subtitle...even though I bought this book AFTER seeing The Empire Strikes Back). The screenplay I read included scenes that were later edited out of the final film (mainly scenes on Tatooine focusing a bit on Luke's life there and introducing Biggs Darklighter. Another deleted scene -- later restored for the Special Edition 20 years later -- introduced Jabba the Hutt...he would have been very different in look and demeanor from the final Jabba, but at least he was there. Some of these scenes appear both in the novelization (make that ALL) and in the Radio Drama.
The other attractive thing of this book was the amazing artwork. It ranges from pre-production paintings, costume concepts, actual photos, storyboards, and poster art. It even has a section devoted to spinoff art and some cute fan art, mostly drawn by small children.
The one flaw in the book is not content related but the choice of paper and binding. The pages are glossy, like those of a yearbook...but the glue that holds the pages to the binding was not strong enough to hold the pages together. I went through three copies of this book in the time it was in print...I only looked at the last one ONCE and the pages still came loose. Thus, out of 5 stars, I give this book 4.