This book provides a mathematical approach to music composition. Although this topic has attracted significant attention, existing efforts focus on algebra and number theory. We add to the literature of applied mathematics by leveraging stochastic processes to compose chamber music. The first several chapters of the book introduce key concepts from probability theory. Subsequent chapters explore elements of music theory, such as atonality, chord, mode, scale, and tonality, and demonstrate how to connect them with concepts in probability theory. Later chapters outline a C++ program to generate note indices and finally formulate a measure for a string quartet. This book is intended for students with prior coursework in introductory C++, probability theory and stochastic processes, and music theory I and II. Potential future research directions in this field are also highlighted.