The manufacture and structure of leather in general and the characteristics of the most commonly used species, i.e., calf, sheep, goat, pig, boxcalf, <i>chevreau</i>, and chamois leather, are described. Leathermaking in the 18th century in Mechelen, Belgium is also described. New leather for restoration purposes should not be colored and should have a pH value of 4-6. For dyeing, BASF dyes are recommended, and for gluing, polyvinyl acetate emulsion (Mowilith DMC 2). Replacement pieces are thinned down on their edges to make a better join. Leather will be preserved if the acidity, water, and fat levels are those recommended. Storage should be at 18-20°C, relative humidity at 50-60%, with light intensities 50-150 lux and all ultraviolet radiation filtered out. Examples of restored objects are given.