This is a brief expositary account of Boson stochastic calculus which includes a description of quantum Ito’s formula and
its application to the integration of a master equation in statistical mechanics.
Keywords Quantum dynamical semigroup - Weyl representation - Boson Fock space - annihilation - creation and gauge processes - adapted process - Ito’s formula - quantum Poisson field - Schrödinger equation in the presence of noise - Gorin-Kossakowski-Sudarshan-Lindblad equation