The anomalous Hall effect (AHE) is one of the oldest and most prominent transport phenomena in magnetic materials. Yet, AHE has remained unresolved for more than a century because its rich phenomenology defies standard classification, prompting conflicting claims of the dominant mechanisms. In this lecture, I will give a comprehensive discussion on the basic concepts on AHE. Expoliting the attributes of epitaxial magnetic thin films, I will then explain how to control independenly the different scattering processes through temperature and layer thickness and to identifiy unambiguously the intrinsic mechanism as well as the extrinsic mechanisms of the AHE. Based on the understanding of the microscopic mechanisms of the AHE, I will describe how we develop a new method using the H-patterns to measure quantities inherent to the SHE.