Pectins are one of the classes of complex structural plant cell wall polysaccharides. They are localized in the middle lamella and primary cell wall of higher plants. Pectins have a long-standing use as gelling agents whereas their enzymatic degradation or modification plays an important role in the processing of agricultural crops and the manufacturing of foods and beverages. Progress in pectin and pectinase research has been most prominent in two areas over the past 5 years. The first one concerns the analysis and elucidation of the complex chemical structure of pectin and identification of novel enzymes involved in the degradation of these structures. The second area concerns the mode of action and the 3-dimensional structure of various pectin degrading enzymes as well as the cloning of a large number of genes encoding enzymes involved in pectin degradation and modification. This book covers the following topics. First the structural, physic