Adhesion, adhesives and adherents are elements of a general adhesion technology which is of great importance to many fields of engineering, including the gluing of wood. Glue joints play and important role in economical woodworking since they allow the improvement of blockboards and of lowgrade plywood cores by veneering, the manufacture of rather complicated constructions, the production of plywood and laminated board, beams and arches, the utilization of smaller wood sections and the binding in particleboards, Practically no wood based material — except densified solid wood and flexible wood — is manufactured without gluing of sheets or particles.