I picked up the 1956 edition of the Complete Guide to Disneyland. In the first two years that Disneyland was open, this is the third, completely different format. The first edition featured concept art work as Disneyland was virtually under construction until opening day and there was no time to include actual photos. There was a second Guide Book, also published in 1955, but this one was basically a collection of photos that were already available as postcards.
With the 1956 Guide Book, Disney would lock-in to a format that they would keep for many years. The Guide Books in the early years weren't jammed packed with information. This edition only comes in at 26 pages. But, what is included are gems for Disney collectors. The Crane Bathroom of Tomorrow, The Flight Circle, and we also get concept art for Rainbow Caverns Mine Train, Tom Sawyer Island and Storybook Land (seen below).