Plywood is not only the oldest of the range of wood-based panels but it is also the most variable panel product, encompassing a wide range of timber species cut into veneers of differing thicknesses which are bonded together with a range of adhesives to give plywoods with lay ups of different appearances, colours, density and performance. Whilst plywood has many major attributes as a sheet material, its greatest weakness lies in its extensive variability. Characterisation and quantification of this variability has represented a major challenge over many decades to the efficient use of plywood. This Digest describes this product and provides guidance on its use when manufactured to the European Standard EN 636. It demonstrates how, when the product is used in construction within Europe, mandatory compliance with the Construction Products Directive can be achieved by using the new European Harmonised Standard (EN 13986). 8 pages.