This paper presents a 50-year tutorial review of multiple access (MA) technologies, focusing on their evolution and key developments in both the power domain and spatial domain. The review highlights the foundational principles and information-theoretic limits of power-domain non-orthogonal multiple access (NOMA), its extension to MIMO-NOMA, and the application of NOMA in integrated sensing and communications (ISAC) systems. It also explores various MA transmission schemes in the spatial domain, including conventional space-division multiple access (SDMA)/MIMO-NOMA systems and near-field MA systems. The paper discusses the integration of MA with emerging technologies such as 6G, and identifies major research opportunities for future MA and next-generation multiple access (NGMA) systems. The review emphasizes the shift from orthogonal to non-orthogonal transmission strategies, driven by the need for enhanced spectral efficiency and performance in modern wireless communication systems. Key contributions include the exploration of information-theoretic limits of power-domain NOMA, an overview of spatial-domain MA transmission schemes, and the integration of NOMA with ISAC systems. The paper also identifies promising research directions in NGMA, including new application scenarios, techniques, and tools. The review aims to provide a comprehensive perspective on MA technologies, their applications, and future research opportunities.This paper presents a 50-year tutorial review of multiple access (MA) technologies, focusing on their evolution and key developments in both the power domain and spatial domain. The review highlights the foundational principles and information-theoretic limits of power-domain non-orthogonal multiple access (NOMA), its extension to MIMO-NOMA, and the application of NOMA in integrated sensing and communications (ISAC) systems. It also explores various MA transmission schemes in the spatial domain, including conventional space-division multiple access (SDMA)/MIMO-NOMA systems and near-field MA systems. The paper discusses the integration of MA with emerging technologies such as 6G, and identifies major research opportunities for future MA and next-generation multiple access (NGMA) systems. The review emphasizes the shift from orthogonal to non-orthogonal transmission strategies, driven by the need for enhanced spectral efficiency and performance in modern wireless communication systems. Key contributions include the exploration of information-theoretic limits of power-domain NOMA, an overview of spatial-domain MA transmission schemes, and the integration of NOMA with ISAC systems. The paper also identifies promising research directions in NGMA, including new application scenarios, techniques, and tools. The review aims to provide a comprehensive perspective on MA technologies, their applications, and future research opportunities.