It is a brown book with leather binding and a spiky-looking front cover. It has yellow pages, so this could mean that it is worn-out or old. The same leather binding appears again in the front page reading, "Shalmon Secrets" in a cursive-like font in a burgundy color.
Role in episode
After Shalmon states that "Nuts are meant to be eaten," and that it is all in his book, Shalmon drops the book on top of SpongeBob causing him to sink into the sand. After getting out of the sand, SpongeBob then reads the book in order to understand that nuts are supposed to be consumed.