Stokes' theorem connects surface integrals of a vector field's curl to line integrals around the boundary, making it essential in vector calculus for analyzing flux in three-dimensional space. The document outlines the definitions and applications of vector calculus concepts like line and surface integrals, closed surfaces, and the conditions necessary for applying Stokes' theorem in contexts such as physics and engineering. Visual representations and calculation examples demonstrate the practical implications of Stokes' theorem in various fields.