Sketchbooks come in a wide variety of shapes and sizes, with varied covers, and differing numbers of pages. Sketchbooks began as a way to provide a readily available supply of drawing paper in the convenient form of a book. Finish of the work found in the sketchbook varies widely depending on the artist and their style of work, with some having very simple drawings and notes, and some having highly worked images. Over time, it might allow others to see the artist's progress, as their style and skills develop. Many artists personalize their sketchbook by decorating the covers. Sketches are sometimes removed from sketchbooks at a later date.