The photo-micrographs here included have been arranged on an alphabetical catalogue of all those timbers which are in common use, and are X 10 throughout. It is hoped to follow this by a supplement, since it has been found impossible to complete the entire list in one volume. The first installment includes 504 photo-micrographs and the order following the text of Timbers of the World . The book is very useful for Identification and to know wood structure.