This manual provides comprehensive coverage of oil engines of the compression-ignition type for industrial (stationary and transportable), railway traction and marine duties produced by member firms of the British Internal Combustion Engine Manufacturers' Association. Packed with 247 pages of detailed tables, illustrations and technical data, it is an essential reference for engineers, designers and operators concerned with British diesel engine technology. The first-edition catalogue systematically presents technical specifications, performance curves, dimensional data and application notes for British-made diesel engines, organized by duty type: industrial, marine, and rail traction. Supplemented with engineering drawings and comparative tables, it functions as both historical documentation of mid-20th-century diesel technology and a practical reference for engineering design and maintenance. The volume reflects collaborative standardization efforts among manufacturers and highlights design evolution and interoperability concerns within the British diesel industry.