This book aims to address a wide range of topics in wireless/satellite communications to tackle the issues related to the integration of terrestrial networks (TN) with non-terrestrial networks (NTN). In Release 17, the third-generation partnership project (3GPP) proposed the standardization of NTN to allow 5G-based TN to support NTN. According to Release 17, the NTN will consist of satellites, with unmanned aerial vehicles (UAVs) and high-altitude platforms (HAPs) regarded as specific use cases of NTN. Similar to the Global Positioning System (GPS), signals based on NTN are unable to provide indoor coverage, as these signals are attenuated and scattered by roofs, walls, etc. Moreover, power and delay are critical factors that restrict a cellular-enabled mobile handset from achieving reliability, seamless coverage, and low latency while relying on NTN. This book has brought together multidisciplinary contributors in the field of wireless/satellite communications to identify and present technical challenges and recent results related to the design of energy-efficient, delay-tolerant, and enhanced coverage-based integrated TN and NTN. Given that challenges and future aspects are also considered, the book covers a wide variety of subject categories and would therefore benefit a larger readership in the scientific community.