This SpringerBrief explores the technological, economic, physiological, and psychological comparisons between a journey to the Moon versus a journey to Mars, taking into consideration the national and international perspectives at play. The author spent over six years interviewing leading space experts from around the world to learn why lunar habitats and the creation of a permanent presence on the Moon are an essential next step to human exploration and settlement in space. Practical reasons related to energy, telecommunications and networking, robotic systems, medical and scientific research, material processing, and more show why it must be the Moon First and Mars Second. These findings and recommendations have been adopted by current NASA Administrator Jim Bridenstine, as well as the current U.S. president. The research in this text reflects the author's experiences working internally within NASA Headquarters, the FAA Commercial Spaceflight Office, as well as the International Space University.