This document’s purpose is to provide pipeline operators with historical data on line pipe, so that they will be able to operate their pipelines, particularly the older ones, with greater confidence in their safety and reliability. The document is comprised of four major sections. The first explains the manufacturing processes that have been and are being used to make line pipe. The second presents tables by type of pipe listing the manufacturers of line pipe, past and present, in North America. At the end of this section some techniques for identifying unknown pipe samples are presented. In the third section the API line pipe specifications as they have evolved since 1928 are reviewed. The fourth section is a glossary of terms frequently associated with line pipe manufacturing.