Layers? - What Layers? is a collection of cartoons about Computer Aided Design and its management by cartoonist and former architect Roger Penwill. As an architect in London Roger was responsible for introducing CAD into the practice, so he has known the sweat and tears of management of the software. He has been there, done that and drawn the tee-shirt. His first two collections of CAD cartoons were published some years ago. It's time for a new one. Here it is.