The Special Issue "Advanced Control, Optimization, Stability and Reliability of Microgrids and Power Systems", published in Energies, presents a collection of 17 rigorously reviewed research and review papers addressing key challenges in modern power and energy networks. As global power systems transition toward higher penetration of renewable energy, distributed generation, energy storage, and power electronic converters, maintaining system stability, operational efficiency, and reliability has become increasingly complex. This Special Issue provides timely contributions to these challenges. The papers cover a wide range of topics, including time-domain stability analysis of multi-machine microgrids, AC and DC inertia enhancement strategies for converter-dominated systems, coordinated active and reactive power optimisation in distribution network-microgrid clusters, and mitigation of three-phase imbalance in low-voltage networks. Several contributions introduce control techniques such as adaptive sliding mode control, emergency frequency control strategies, neural-network-based compensation methods, and distributed edge-agent frameworks. Data-driven approaches are also explored, including robust multi-level state estimation under communication delays, power oscillation source location using data-driven methods, and reliability assessment based on Bayesian networks. A comprehensive review paper outlines progress and future directions in microgrid optimisation, power prediction, and virtual synchronous generator control.