This publication covers control sytems that employ proportional control elements, e.g. proportional control valves and hydrostatic transmissions, and gives extensive treatment to system modelling including algorithms for computer-based analysis. The three main features of this book are: description and analysis of closed-loop servo systems, and open and closed-loop systems using proportional control valves; a novel rationalized approach to a wide range of system configurations, including flow feedback systems; and a new modular computer program structure including automatic system optimization, performance trends as a function of any independent variable, and transient response to any given duty cycle. The book essentially studies and analyzes force and motion control systems - from simple hydraulic to complex electro-hydraulic control systems - bridges the gap in knowledge between the control engineer and the average hydraulic application engineer, and provides a contribution towards the wider application of hydraulic systems. This second enlarged edition includes an entirely new addition - a tutor for the application of "Hydro Analyst". The tutor provides a "hands-on" system simulation procedure for the system modelling package "Hydro Analyst" supplied with this edition as a floppy disk. The package contains an extensive component database and comprehensive graphics facilities. This book should be of interest to engineers working in hydraulics and control.