This SpringerBrief discusses the origins, emergence, evolution, and future of the Technology Acceptance Model (TAM). TAM, simple yet powerful, has been extensively validated, standing as a leading scientific paradigm and a reliable model for explaining, predicting, and improving user acceptance across a spectrum of technological deployments. Over more than three decades since the introduction of TAM, numerous extensions have emerged, incorporating additional variables and collectively referred to as "e;TAM++"e;. However, perceived usefulness and perceived ease of use remain the basic beliefs of the core TAM model. The introductory chapter "e;Once upon a TAM"e; focuses on the challenging search for a user acceptance crystal ball, showing that it is indeed possible to consistently predict, explain, and improve user acceptance. "e;Evolution of TAM"e; traces the model's growth and adaptability, exploring the proliferation of selected TAM-related behavioural intention models, several integrated theoretical approaches, the quest for other behavioural intention antecedents, and TAM's versatile applications in various contexts. "e;Revolution of TAM"e; presents an in-depth systematic review, encompassing a meta-analysis of selected TAM reviews and meta-analyses, and a narrative review of representative primary studies, providing a thorough and extensive understanding of the TAM universe. The epilogue "e;What will the Future of TAM be Like?"e; provides insights into its dynamic future. This SpringerBrief concludes with seven actionable principles, serving as a strategic guide for those aiming to customize the TAM++ body of knowledge for application-oriented studies within a particular context. This comprehensive overview of TAM is a valuable source of information for researchers, practitioners, and all interested readers, especially those new to the field.