This book deals with the functioning of hydrodynamic journal bearings in turbomachinery. It makes particular reference to large turbine generator and marine propulsion plant. Journal-bearing design in this field has been based mainly on experience supplemented by full-scale experimental test. Development is becoming influenced to an increasing extent by research and analysis. Particular attention is given in this book to correlation of research and analytical work with the observed operating characteristics of journal bearings. The physical phenomena in bearings are complicated, and analysis is rendered convenient only by making simplifying assumptions. The engineer must know which assumptions are serviceable and in what operating conditions they may be applied. Current British and European practice in journal bearings is illus trated. An examination is made of steady running characteristics, as predicted by theory and as established by test. Some account is given of the dynamic characteristics of journal bearings and of their in fluence in machine vibration. Service experience of journal bearings is reviewed, and reference is made to possible future trends in develop ment. The book is the outcome of work on turbine plant with Metropolitan Vickers and its successor Associated Electrical Industries. The A.E.!. and English Electric activities in this field have recently been incor porated in English Electric-A.E.!. Turbine-Generators Ltd. The author expresses his gratitude to the Company for permission to publish the results. He thanks the English Electric Co. Ltd., C. A.