Criminology is an interdisciplinary field that uses a scientific approach to examine crime, criminal conduct, its origins, and society's reaction to criminality. From pre-scientific explanations to modern integrated approaches, this article critically examines the definition, scope, and nature of criminology and outlines its historical growth. It highlights their contributions and limitations while evaluating the most prominent schools of criminological thinking, such as the Classical, Neo-Classical, Positivist, Sociological, Critical, and Feminist schools. Life course, labelling, and differential association theories are also addressed in the study, as are anomie, social disorganization, and strain theories. Additionally, it links criminological theories to the Indian legal and constitutional system, which includes the Bharatiya Nyaya Sanhita of 2023, the Bharatiya Nagarik Suraksha Sanhita of 2023, the Juvenile Justice Act of 2015, and the Probation of Offenders Act of 1958. Relevant Indian case laws are examined to show how deterrent, retributive, reformative, and rehabilitative approaches affect criminal justice. The study ends by stating that modern criminology is using an integrated, evidence-based method more often, seeing crime as a multi-causal occurrence affected by individual, social, structural, and developmental elements.