This monograph, titled "An Introduction to Quantum Stochastic Calculus," is authored by K.R. Parthasarathy and published by Springer Basel AG as part of the "Monographs in Mathematics" series (Vol. 85). The book explores the theory of quantum stochastic calculus, which combines quantum theory and stochastic processes. It is divided into three chapters: 1. **Events, Observables and States**: This chapter discusses the classical to quantum probability transition, spectral integration, Stone's Theorem, unbounded operators, and the Wigner's Theorem on automorphisms. 2. **Observables and States in Tensor Products of Hilbert Spaces**: It delves into positive definite kernels, tensor products of Hilbert spaces, symmetric and antisymmetric tensor products, quantum stochastic flows, Fock spaces, the Weyl Representation, and creation, conservation, and annihilation operators. 3. **Stochastic Integration and Quantum Ito's Formula**: This chapter covers adapted processes, stochastic integration with respect to creation, conservation, and annihilation processes, quantum stochastic differential equations, Evans-Hudson flows, and generators of quantum dynamical semigroups. The preface provides an overview of the book's motivation, historical context, and key contributions. It highlights the relationship between quantum probability, infinitely divisible distributions, and the Weyl representation, as well as the development of quantum stochastic calculus. The author acknowledges the influence of various scholars and colleagues, expressing gratitude for their support and contributions to the field.This monograph, titled "An Introduction to Quantum Stochastic Calculus," is authored by K.R. Parthasarathy and published by Springer Basel AG as part of the "Monographs in Mathematics" series (Vol. 85). The book explores the theory of quantum stochastic calculus, which combines quantum theory and stochastic processes. It is divided into three chapters: 1. **Events, Observables and States**: This chapter discusses the classical to quantum probability transition, spectral integration, Stone's Theorem, unbounded operators, and the Wigner's Theorem on automorphisms. 2. **Observables and States in Tensor Products of Hilbert Spaces**: It delves into positive definite kernels, tensor products of Hilbert spaces, symmetric and antisymmetric tensor products, quantum stochastic flows, Fock spaces, the Weyl Representation, and creation, conservation, and annihilation operators. 3. **Stochastic Integration and Quantum Ito's Formula**: This chapter covers adapted processes, stochastic integration with respect to creation, conservation, and annihilation processes, quantum stochastic differential equations, Evans-Hudson flows, and generators of quantum dynamical semigroups. The preface provides an overview of the book's motivation, historical context, and key contributions. It highlights the relationship between quantum probability, infinitely divisible distributions, and the Weyl representation, as well as the development of quantum stochastic calculus. The author acknowledges the influence of various scholars and colleagues, expressing gratitude for their support and contributions to the field.