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 rationalised approach to a wide range of system configurations, including flow feedback systems; A new modular computer program structure including automatic system optimisation, performance trends as a function of any independent variable, and transient response to any given duty cycle. The book essentially studies and analyses 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 will be of interest to engineers working in hydraulics and control.