1. Before 2023 BS: the Muluki Ain 1910's transaction chapters (the Lendenko Mahal, Prarambhikko Mahal, Naso Dharotko Mahal — the loan-and-security chapters of the classical Ain); the custom-and-usage regime;
2. The Contract Act, 2023 BS (1966): the first separate contract statute (the Indian Contract Act 1872's structural cousin);
3. The Contract Act, 2056 (2000): the modern statute — the general contract law + the nominate contracts; the consideration doctrine's codification; the judicial era's base (the prescribed cases' earlier vintage);
4. The Muluki Civil Code 2074 (in force Bhadra 1, 2075 / 17 August 2018):Part V (thesections 493–671 family, 16 chapters) — the contract-and-obligations law unified into the Code (the Contract Act 2056 repealed by the 2074 adjustment legislation); ~70% carried from the 2056 Act with the modernizations (the formality rules; the good-faith standard; the jyala-majduri wage-work contract's new chapter) — the current law of this course.