The document discusses different types of lines used in drawing. It describes descriptive lines such as outlines, contour lines, and hatching/cross-hatching lines which help define shapes. Implied lines are also discussed, which suggest edges rather than clearly defining them, through textures, values or lines of sight. Expressive lines are meant to convey emotion and send messages about how the artist wants the viewer to feel. The document provides examples to illustrate the different line types.