This up-to-date reference book is for professionals active in subsea production systems and in particular those engaged in the control and monitoring of such installations. Dealing exclusively with underwater instrumentation, control, and communication technology for subsea oil and gas production, this volume has been structured to cover a wide range of subjects, specifically those technologies that enable field optimisation. Optimising field production has predominantly been associated with subsea separation, downhole separation, and smart well development. These interesting technologies are thoroughly covered by authors with considerable experience in the design and application of this technology. as a significant amount of interest has recently been rekindled in buoy-based systems, this text revisits this subject to determine the state of the art. Topics covered include: optimising field performance; buoy-based systems; intervention; systems architecture and sensors; experience feedback; subsea communication. A volume of this nature is not complete without relevant papers on experience feedback and reliability. We are therefore able to include contributions from experts who have experience with the Foinhaven, Schiehallion, Troika, and Pompano projects as well as the use of materials subsea and the problems experienced. This book should be of interest to engineers and others in this international field keen to keep up with current practices and technologies.