This book will sell because it outlines a method by which the failure of
control systems can be circumvented. The reader will be interested
either because it can extend the period of plant operation between
costly overhauls or because the effect of a sudden uncompensated failure
in control would be dangerous (in an airborne aircraft for example)
where the techniques exemplified in this book will keep the control
systems effective long enough to be able to wind them down safely (in
time to land the aircraft for example).