This TECDOC presents a comprehensive review of the current status and future prospects of nucleonic gauge methodology and technology applied as nucleonic control systems (NCS) to a broad spectrum of industrial engineering processes. It presents the results of the IAEA's Advisory Group Meeting on Emerging New Applications of Nucleonic Control Systems in Industry, which was convened to discuss and evaluate the present 'state-of-the-art' of this field. The TECDOC provides fundamental information on the principles of nucleonic gauges, their design, safe operation and applications. This covers both the more traditional and well established applications and methods as well as trends on emerging applications of new nucleonic gauges in modem industry. A specific review is presented of nucleonic gauge methodology and technology as applied in international priority industrial sectors such as the petroleum industry, mining and mineral ore processing, material construction and environment. This information on nucleonic gauges, including the most relevant recent achievements and developments, effectively enhances and often replaces the existing related publications, many of which have lost their relevance. Separate abstracts have been prepared for the thirteen individual country reports included in this TECDOC.