This course explores the European Union's Artificial Intelligence Act (AI Act), finalized in 2024, with a focus on its transparency and explainability requirements for AI systems. It introduces the TEFT (Transparency-Explainability Functionality and Tensions) framework, which helps analyze the legal, technical, and ethical challenges of implementing these requirements in practice. Through literature review and a detailed examination of the AI Act, the course maps the interests, risks, and goals of key stakeholders — including AI providers, regulators, and affected individuals — highlighting the tensions between transparency and the protection of intellectual property.