This paper reviews the theoretical basis and applications of QCD sum rules to hadronic physics, as developed by Shifman, Vainshtein, and Zakharov. The authors discuss the general procedure, including the calculation of Wilson coefficients for perturbative and nonperturbative operators, and apply these methods to two-point and three-point functions of heavy and light quark systems, as well as mesons and baryons. They also explore the use of moments and the Borel transform to enhance the dominance of the lowest lying resonance in the sum rule. The paper covers the calculation of masses and couplings of resonances, and provides a detailed review of the phenomenology of two-point functions, including charmonium, upsilonium, light quark mesons, and systems with one light and one heavy quark. Additionally, it discusses three-point functions and their applications to hadron couplings of Goldstone bosons, trilinear meson couplings, and baryon couplings to pions and kaons. The authors conclude by summarizing the results and discussing the limitations and future directions of the QCD sum rule method.This paper reviews the theoretical basis and applications of QCD sum rules to hadronic physics, as developed by Shifman, Vainshtein, and Zakharov. The authors discuss the general procedure, including the calculation of Wilson coefficients for perturbative and nonperturbative operators, and apply these methods to two-point and three-point functions of heavy and light quark systems, as well as mesons and baryons. They also explore the use of moments and the Borel transform to enhance the dominance of the lowest lying resonance in the sum rule. The paper covers the calculation of masses and couplings of resonances, and provides a detailed review of the phenomenology of two-point functions, including charmonium, upsilonium, light quark mesons, and systems with one light and one heavy quark. Additionally, it discusses three-point functions and their applications to hadron couplings of Goldstone bosons, trilinear meson couplings, and baryon couplings to pions and kaons. The authors conclude by summarizing the results and discussing the limitations and future directions of the QCD sum rule method.