In this text Ruskin reduces the art of drawing to its simplest elements - the making of marks, the perception of shapes and silhouettes. His method emphasizes the importance of observation, over and above the production of pictures, and of graduated study. Bernard Dunstan has now written an introduction and a commentary on the text where its relevance today seems to need interpretation, and has added his own drawings and colour exercises to illustrate more fully Ruskins's method and instruction. Whenever Ruskin mentions other painters - Titian, Durer, Turner and so on - as examples, Dunstan reproduces the actual paintings he talks about, or a drawing after the painting.