In this comprehensive classic manual, the author describes the use of timber as bridge material, types of timber bridges, the properties of wood and wood products, preservation and protection of timber bridges, timber design concepts for bridges, loads and forces on timber bridges, design of beam superstructures, design of longitudinal deck superstructures, design of longitudinal stress-laminated deck superstructures, rail systems for timber decks, wearing surfaces for timber decks, timber bridge fabrication and construction, bridge inspection of decay and other deterioration, maintenance, rehabilitation and replacement of timber bridges. This is a digitally recreated publication of the original manuscript (1990), comprising over 900 pages, produced in its entirety. Wood was probably the first material used by humans to construct a bridge. Although in the 20th century concrete and steel replaced wood as the major materials for bridge construction, wood is still widely used for short- and medium-span bridges. Of the bridges in the United States with spans longer than 20 feet, approximately 12 percent of them, or 71,200 bridges, are made of timber. In the USDA Forest Service alone, approximately 7,500 timber bridges are in use, and more are built each year. The railroads have more than 1,500 miles of timber bridges and trestles in service. In addition, timber bridges recently have attracted the attention of international organizations and foreign countries, including the United Nations, Canada, England, Japan, and Australia.