1.1 Introduction1.2 Rationale Behind MTDC Grids1.3 Network Architectures of MTDC Grids1.4 Enabling Technologies and Components of MTDC Grids1.5 Control Modes in MTDC Grid1.6 Challenges for MTDC Grids1.7 Configurations of MTDC Converter Stations1.8 Research Initiatives on MTDC Grids1.9 Focus and Scope of the Monograph