The lecture discusses CP violation in the Standard Model (SM) and its extensions. It reviews the KM mechanism, which explains CP violation in the SM through a complex phase in the quark mass matrix. The KM mechanism is linked to the observed CP violation in K meson mixing. However, the origin of this phase remains unclear, and the question of whether CP violation arises from a single source or multiple interactions is still unresolved. The dynamics of electroweak symmetry breaking is another major enigma in particle physics, and these two issues are likely connected. The lecture also explores CP violation in extensions of the SM, such as multi-Higgs and supersymmetric models. In these models, explicit CP violation can arise from complex phases in the Higgs potential or in the soft supersymmetry breaking terms. These models can lead to CP violation in various interactions, including those involving neutral Higgs bosons and charged Higgs bosons. The presence of CP violation in these models can be tested in experiments, such as those searching for electric dipole moments (EDMs) of particles. The lecture discusses the implications of CP violation in weak decays of strange, charmed, and beauty hadrons. It highlights the importance of measuring CP asymmetries in these decays to test the KM mechanism and to search for new CP-violating interactions. The search for EDMs is a sensitive probe of CP violation, as a non-zero EDM would indicate P and T violation, which is a signature of CP violation under CPT invariance. The lecture also addresses the strong CP problem, which arises from the small value of the QCD vacuum angle. This problem is not fully understood and is considered a key issue in the SM. The lecture discusses possible solutions to this problem, including the possibility of a non-zero CP phase in the Higgs potential or in the soft supersymmetry breaking terms. In summary, the lecture provides an overview of CP violation in the SM and its extensions, highlighting the key mechanisms, experimental tests, and open questions in the field. It emphasizes the importance of understanding CP violation in both the SM and its extensions for advancing our knowledge of particle physics.The lecture discusses CP violation in the Standard Model (SM) and its extensions. It reviews the KM mechanism, which explains CP violation in the SM through a complex phase in the quark mass matrix. The KM mechanism is linked to the observed CP violation in K meson mixing. However, the origin of this phase remains unclear, and the question of whether CP violation arises from a single source or multiple interactions is still unresolved. The dynamics of electroweak symmetry breaking is another major enigma in particle physics, and these two issues are likely connected. The lecture also explores CP violation in extensions of the SM, such as multi-Higgs and supersymmetric models. In these models, explicit CP violation can arise from complex phases in the Higgs potential or in the soft supersymmetry breaking terms. These models can lead to CP violation in various interactions, including those involving neutral Higgs bosons and charged Higgs bosons. The presence of CP violation in these models can be tested in experiments, such as those searching for electric dipole moments (EDMs) of particles. The lecture discusses the implications of CP violation in weak decays of strange, charmed, and beauty hadrons. It highlights the importance of measuring CP asymmetries in these decays to test the KM mechanism and to search for new CP-violating interactions. The search for EDMs is a sensitive probe of CP violation, as a non-zero EDM would indicate P and T violation, which is a signature of CP violation under CPT invariance. The lecture also addresses the strong CP problem, which arises from the small value of the QCD vacuum angle. This problem is not fully understood and is considered a key issue in the SM. The lecture discusses possible solutions to this problem, including the possibility of a non-zero CP phase in the Higgs potential or in the soft supersymmetry breaking terms. In summary, the lecture provides an overview of CP violation in the SM and its extensions, highlighting the key mechanisms, experimental tests, and open questions in the field. It emphasizes the importance of understanding CP violation in both the SM and its extensions for advancing our knowledge of particle physics.