This article gives a thorough introduction to EU law by discussing its origins, evolution, sources, and guiding principles as well as its institutional architecture. Examining concepts like direct impact, supremacy, and state culpability, it probes the interplay between EU law and domestic law. This article examines the several forms of EU legislation, the procedure for passing new laws, and the function of the CJEU as an interpreter and enforcer of EU law. The free flow of people, products, services, and money are also covered, as are other important areas of EU law such as the internal market and competition law. This article uses applicable case law and judgements to show how EU legislation is put into practice and what kind of influence it has.