All wares made of fired clay except porcelain.
The shaping and baking of clay vessels is among the oldest and most widely practiced of all the crafts; and in quite early times potters already spent much ingenuity on making their wares stylish as well as practical. Even in the Neolithic stages of culture, when pots were often laboriously constructed from superimposed coils of clay, baked in open fires or sometimes merely dried in the sun, their shapes and simple incised or painted ornament were often of no little aesthetic merit. These elementary processes are still in use among primitive groups even today. With the invention of the wheel it became possible to achieve forms of great refinement and variety. The more advanced types of decoration, however, such as glazing and fine painting, and comparatively superior materials such as stoneware and porcelain were only perfected as a result of centuries of tradition and individual experiment. Above all, progress in these fields was dependent on the extremely testing exigencies of the firing-kiln. For these reasons, therefore, the history of the ceramic art is bound up to an exceptional degree with considerations of technique.