"Health and safety is important but what impelled us to put in a power flying system was nothing to do with that, it was because we could get improved artistic control to better serve the director, designer and  choreographer"

This is a great compendium of information relating to elevator mechanisms, stage wagon drives, power flying hoists, control systems, British Standards and many allied topics. It provides details of proprietary Spiralift and Rigid Chain mechanisms as well as screw-jacks, chain and wire-rope lifts, rack and pinion drives and scissor mechanisms.  It has a full review of different types of power flying hoists and well as many fascinating insights into the physical strain caused by handling counterweights, and different ways to change auditorium forms - not all of them mechanical, as a treatise on the working of the Cottesloe demonstrates. There is a full description of the effects of harmonics in power supply systems that can arise from the use of dimmer and motor control equipment in theatres. The book concludes with further safety warnings, this time related to working at height, complete with a practical check list for carrying out risk assessments.  This book is an important read for anyone involved in stage machinery, rigging or technical installations.