Even as developments in photorealistic computer graphics continue to affect our work and leisure activities, practitioners and researchers are devoting more and more attention to non-photorealistic (NPR) techniques for generating images that appear to have been created by hand. These efforts benefit every field in which illustrationsthanks to their ability to clarify, emphasize, and convey very precise meaningsoffer advantages over photographs. These fields include medicine, architecture, entertainment, education, geography, publishing, and visualization.