Wood is the main source of the fibers used in the large-scale industrial production of paper-based products. Paper can be made from other plant fibers such as papyrus, cotton, and flax, but wood has much greater availability. The various characteristics of these plant fibers help develop the properties of different paper products. This course describes the sources of fibers, the various characteristics of these fibers, how they are tested, and their value or impact in the manufacturing of pulp and paper.