This chapter explores the multifaceted challenges and solutions involved in integrating microgrids with the main electricity grid. Microgrids, characterised by low inertia, power electronic interfaces, and unbalanced loads, require advanced strategies for voltage and frequency control, particularly during transitions between islanded and grid-connected modes. The chapter discusses critical components of integration including distributed energy resources (DERs) control modes (grid-forming vs. grid-following), disconnection devices, protection mechanisms, and synchronisation with weak grids. Key technical issues—such as transformer inrush current, grounding systems, and the impact of fault currents—are addressed through practical design recommendations. The role of microgrids in enhancing grid resiliency during natural disasters and emergencies is also emphasised, alongside methods for modelling their stability using dynamic simulations. Control architectures are examined across three levels—primary, secondary, and tertiary—along with centralised, decentralised, and distributed implementations. Furthermore, the chapter highlights the importance of protection strategies tailored to DERs, including AC/DC protection coordination and surge protection. Lastly, the role of energy management systems (EMS) is detailed, encompassing real-time optimisation, uncertainty handling, and economic dispatch, supported by emerging AI-based techniques. By combining robust control, protection, and EMS frameworks, microgrids can be effectively integrated into modern power systems while maintaining operational reliability, safety, and economic performance.