This is a very cute book about a little boy who paints a wall different colors revealing a series of images of animals. Birds, fish, dinosaurs, an elephant, giraffes, an anteater, and finally, a puppy appear as white lines in the paint and then come alive running off or interacting with the little boy in some way. It is a great little wordless picture book that will have little ones quickly turning pages to find out what will appear next.
This would make a good storytime book for interacting with the children asking them to say what the animals are or name the colors being used. It could be followed up by a rubbing craft or wax resist craft so they could reveal their own secret images.
UPDATE: I recently worked on very simple craft where I used a white crayon to draw a variety of Halloween images on different sheets of white paper. With watercolors, we revealed the secret messages and images just like in The White Book!
The prep was very easy and it was a big hit. You could even have a volunteer make the images for you.