The book captioned as “A Treatise on Legal Metrology” not only contains the Legal Metrology Act, 2009 and the operative Rules framed under it but also The Institute of Legal Metrology Rules, 2011. This is important for the State Administrator to know the powers and responsibilities of the Institute. And the expected services from the Institute. Simpler and useful formats with blank tables have been given for recording the test data and final result for sample checking of the net content of packages of pre-packed commodities. For the purpose of updating the knowledge about the base units of the International System of Units, the latest definitions of base units have been cited as comments. Emphasis has been given that there is no separate class for supplementary units. These are dimensionless derived units. All out efforts have been made to include all the Rules made under the Legal Metrology Act, 2009 (1 of 2010).