This highly detailed reference represents an elaborate development of the theory of processing oil and natural gas and its application in the field -- indispensable for graduate engineering students and professionals alike. The renowned expert author, a professor at Moscow State University, has ample experience in both lecturing and publishing, albeit in the Russian language. This book is thus the first to provide a translation compiling his extensive knowledge, much of which remained unpublished due to security restrictions in the former Soviet Union. Based upon and compiled from Professor Sinaiski's university lectures, the first chapters treat the technical facilities for preparing and processing natural hydrocarbon substances. The following systematic approach go on to explain the behaviors of fluids, gases and droplets separately for solutions, suspensions and emulsions, as well as for gas-liquid mixtures. The resulting work is of interest both for senior students as well as for engineers working in this field.