Moore has created an entertaining, ribald mythology surrounding the color blue. It explains everything from why Picasso cut off his ear to why Pictish warriors painted themselves to where Oscar Wilde got the idea for The Picture of Dorian Gray.
Most of the story takes place in 1890's Paris, and tells tales of the Impressionist painters of that time and place with a great deal of poetic license. There is a small, twisted man known as The Colorman, and he produces a very special type of blue paint. He is closely associated with a Muse who is going about Paris in various guises inspiring the painters to greatness.
While I found this book to be quite entertaining, it also required a bit of mental effort on my part. I'm sure I missed about half the jokes because I am not familiar enough with the art and artists involved. I know who Picasso is and know he cut his ear off. I recognize most of the artists' names from a couple of art appreciations classes I've taken. I am aware of the Moulin Rouge because of a Nicole Kidman film I saw many years ago. My tastes in art are somewhat more sophisticated than the dogs playing poker level, but not sophisticated enough to believe Whistler's Mother is actually a good painting. With all that in mind I do recommend this book, with the caveat that is not going to be for everyone.