Multicore systems have become the de facto computing platform for electronic systems, especially since 2005 when the single-core/thread performance hit the power wall. Consequently, integrating an increasing number of processing elements on a single integrated circuit has become one of the primary research goals in both architecture- and semiconductor technology-level design. However, the increasing power density in multicore systems has also led to increasing dark silicon, where a majority of the on-chip resources need to be turned off for avoiding thermal issues. To this end, intelligent power management constitutes a major focus of research in the system-level design of multicore systems. This chapter provides a brief overview of the background knowledge and the related state-of-the-art research. The chapter presents a summary of the causes and effects of power dissipation in electronic systems along with brief descriptions of the more commonly used power reduction methods. The chapter then presents the state-of-the-art research works in power management across different scales of multicore systems: embedded systems, desktops/client PCs, and HPC servers. The chapter also provides a brief overview of the more recent topics related to power management such as power dissipation in 2.5D/3D systems, cross-layer power management, and Al/ML-based power management.