- Kesavananda Bharati Case (1973) established the 'Basic Structure' doctrine. - The 42nd Amendment Act (1976) added words 'Socialist', 'Secular', and 'Integrity' to the Preamble. - The 44th Amendment Act (1978) reversed some changes made by the 42nd Amendment and removed the right to property from the list of Fundamental Rights. - Minerva Mills Case (1980) re-affirmed the Basic Structure doctrine and struck down parts of the 42nd Amendment.