1. Introduction / Tony Kowalski -- 2. Control of test and measuring equipment in a quality system : balances and scales in GLP/GMP/IS09000 / Stephan Weyhe -- 3. Expression of uncertainty for displayed net values / Juergen Ober -- 4. Software validation / B. A. Wichmann -- 5. Errors associated with weighing / Chris Jenkins -- 6. Weights and weighing machines / M. J. Buckley -- 7. Weighing in the pharmaceutical industry / Ted Scorer -- 8. Methods for estimating the uncertainty of electronic balance measurements / John P. Clark and A. Harper Shull.