Meet our new Duo Book series! Each set includes one Notebook and one Sketchbook.; We like to think of them as equally attractive fraternal twins.The Notebook, ruled for jotting notes and making lists, is here to engage; your; analytical left brain. And the Sketchbook, graphed for drawing and; doodling, is here to coax out your creative right brain. (Yep, it's; left =; analytical, right =; creative. We didn't believe it,; either,; but Google says it's true).