To meet the need for a handy reference guide, with all essential theory, data and information needed every day, Gerard Honey has written this Pocket Book. It will be one of the most useful tools in the kit of anyone specifying, installing, maintaining or repairing security systems, either domestic or commercial. Gerard Honey is a practising security installer and consultant. He is a leading writer for the security industry and has written two other acclaimed books, also available from Newnes: Electronic Protection and Security Systems and Intruder Alarms.