"HOLD THOU THE GOOD: DEFINE IT WELL ... " The quotation above from Tennyson, is apt when describing the purpose and achievement of this book. The author is dedicated to his subject-personal health in industry: his research covers practical experience in the U.K. and other lands. In non-technical language the book records many of the causes of ill-health and throws light upon the physical and mental stress with which men and women at work have to contend. Dr. Ffrench's observations and conclusions should be of consider­ able value to employers of labour and of interest to all concerned in the welfare of people engaged in earning a living. HAROLD COOPER Alfred H. Cooper & Sons Ltd Vll Preface This book has been prepared so that readers may appreciate the significant change in attitudes which has taken place over the past twenty-five years towards the care of the health of people at work.