Book excerpt: Advanced Relay Technologies in Next Generation Wireless Communications describes the use of the highly successful cooperative networks/relaying approach in new and emerging telecommunications technologies such as full-duplex radio, massive multiple-input multiple-output (MIMO), network coding and spatial modulation, and new application areas including visible light communications (VLC), molecular communications, wireless power transfer, and 5G. Topics covered include: -spatial modulation for cooperative networks -relaying for massive MIMO; relaying for outdoor to indoor in mmWave communications -precoding techniques for relaying with interference -relaying in full-duplex radio communication systems -relay selection in modern communication systems -relaying in green communications systems -energy-efficient relaying -cognitive radio with relaying -relaying in non-ideal conditions -relaying and physical layer secrecy relaying technologies for smart grid -simultaneous wireless and power transfer for interference relay channel -relaying in visible light communication systems -on-ground and on-board signal processing for multibeam precoding.