Pose guide Books are items which can be used to let your family learn new Poses. You can strike a pose with a character in-game to take interesting screenshots. The variety of poses changes with each different guide book.
Obtained From Edit
Pose Guide Volumes 2-9 can be bought from Andre Janzur in Reboldeaux for vis. Pose Guide Volume 1 is given as a reward for completing the quest Template:Kill Mandradora, also obtained from Andre Janzur.
To see what the individual poses all look like, visit the relevant pages: