A Guide to Random Process is a comprehensive textbook that introduces the fundamental concepts and applications of random processes in engineering, mathematics, and applied sciences. The book covers probability theory, stochastic processes, random variables, stationary and ergodic processes, Markov chains, Poisson processes, Gaussian processes, spectral analysis, and random signal analysis. It emphasizes both theoretical foundations and practical problem-solving through illustrative examples, worked-out exercises, and real-world applications in communications, signal processing, control systems, finance, and data science. Designed for undergraduate and postgraduate students, researchers, and professionals, this book serves as a reliable resource for understanding and applying random process theory in modern scientific and engineering disciplines.