It is a system of thought and explains crime in its own manner and suggests punishment and preventive measures to suits its ideology.
1. Pre classical School (Demonological Theory),
2. Classical School (Free will Theory),
3. Neo Classical School,
4. Positive School (Italian school),
5. Sociological school,
6. Geographical School,
7. Clinical School,
8. Mental Testers School (Mental Deficiency Theory),
9. Socialistic School (Economic Theory)