The paper provides a comprehensive tutorial review on multiple access (MA) technologies, focusing on their evolution over the past 50 years. It highlights the foundational principles and information-theoretic capacity limits of power-domain non-orthogonal multiple access (NOMA) and its extension to multiple-input multiple-output (MIMO)-NOMA. The paper also explores spatial domain MA transmission schemes, including conventional space-division multiple access (SDMA)/MIMO-NOMA systems and near-field MA systems using spherical-wave propagation models. Additionally, it studies the integration of NOMA with integrated sensing and communications (ISAC) systems, presenting novel frameworks and an analytical framework based on mutual information (MI). The paper identifies research opportunities in next-generation multiple access (NGMA) systems, emphasizing new application scenarios, techniques, and tools such as semantic communications, reconfigurable intelligent surfaces (RISs), and machine learning (ML). The review aims to provide valuable insights into the design of NGMA systems and serve as a primer for graduate students and researchers in the field of MA.The paper provides a comprehensive tutorial review on multiple access (MA) technologies, focusing on their evolution over the past 50 years. It highlights the foundational principles and information-theoretic capacity limits of power-domain non-orthogonal multiple access (NOMA) and its extension to multiple-input multiple-output (MIMO)-NOMA. The paper also explores spatial domain MA transmission schemes, including conventional space-division multiple access (SDMA)/MIMO-NOMA systems and near-field MA systems using spherical-wave propagation models. Additionally, it studies the integration of NOMA with integrated sensing and communications (ISAC) systems, presenting novel frameworks and an analytical framework based on mutual information (MI). The paper identifies research opportunities in next-generation multiple access (NGMA) systems, emphasizing new application scenarios, techniques, and tools such as semantic communications, reconfigurable intelligent surfaces (RISs), and machine learning (ML). The review aims to provide valuable insights into the design of NGMA systems and serve as a primer for graduate students and researchers in the field of MA.