Abstract
In complex analysis, the evaluation of contour integrals is fundamentally linked to the concepts of residues and winding numbers. This paper provides a comprehensive proof demonstrating the equivalence of contour integrals to the product of residues and winding numbers. Additionally, it elucidates how residues and winding numbers can be expressed in terms of derivatives of specific functions, highlighting their intrinsic connections to function behavior around singularities. Furthermore, the paper extends these foundational concepts to more complex scenarios involving higher-order poles, essential singularities, multi-dimensional contours, and applications in advanced fields such as quantum mechanics and electrical engineering. The exploration includes intricate mathematical derivations, generalizations, and the interplay between topology and complex analysis, thereby enriching the theoretical framework of complex integration.