This section provides a comprehensive introduction to biomedical engineering, tracing its definition, scope, historical evolution, core disciplines, applications, and ethical, legal, and societal considerations. It begins by defining biomedical engineering as an interdisciplinary field that integrates engineering, medical, and biological sciences to develop innovative healthcare solutions, emphasizing problem-solving, system design, and translational applications (Sect. 1.1). The historical development of the field is then explored (Sect. 1.2), highlighting key milestones, hallmarks such as innovation and interdisciplinarity, and the emerging role of artificial intelligence. Core domains, including biomechanics, biomaterials, computational modeling, medical imaging, and medical device design are examined alongside their practical applications in tissue engineering, prosthetics, wearable devices, robotics, minimally invasive surgery, and diagnostic technologies (Sect. 1.3). Finally, the section addresses ethical, legal, and social responsibilities, encompassing patient safety, regulatory compliance, privacy, equity, and sustainability, illustrating the broader societal impact of biomedical engineering (Sect. 1.4).