A few very minor editorial changes are made in order to "Americanize" some phrases.Because of the importance of the SI to science, technology, and commerce, and because NIST (i) coordinates the Federal Government policy on the conversion to the SI by Federal agencies and on the use of the SI by U.S. industry, (ii) provides official U.S. representation in the various international bodies established by the Meter Convention (see p. 1), and (iii) is responsible for interpreting and modifying the SI for use in the United States, NIST provides a number of other sources of information on the SI in addition to NIST SP 330.This includes NIST Special Publication 811, Guide for the Use of the International System of Units (SI), by David B. Newell and Eite Tiesinga.NIST SP 330, NIST SP 811, the aforementioned Federal Register notice are the essential elements of the U.S. interpretation of the SI.