2014 Reprint of 1963 Edition. Full facsimile of the original edition, not reproduced with Optical Recognition Software. Stratonovich was a Russian physicist, engineer, and probabilist and one of the founders of the theory of stochastic differential equations. The genesis of this book, the first of two volumes concerned with various topics in the theory of random noise, is evidenced in the author's remark, "Random processes are of great and ever increasing interest to scientists and engineers working in various branches of radio physics." The major context and relative emphases of this book are well summarized by detail of the part and chapter headings and the pertinent corresponding page numbers: Part I-GENERAL THEORY OF RANDOM PROCESSES: [Chapter] 1. Random functions and their statistical characteristics (3-20), 2. Stationary random processes and spectral densities (21-37), 3. Gaussian and non-Gaussian random processes, quasi-moment functions (39-54), 4. Markov processes and related processes (55-129), 5. Nonstationary random process (131-141), 6. Systems of random points and related random functions (143-176). 7. Narrow-band random processes (177-200); Part II-NONLINEAR TRANSFORMATIONS OF SIGNALS AND NOISE: 8. Zero-memory nonlinear transformations (203-242), 9. Nonlinear transformations with memory, detections of random signals (243-286).