In separate sections covers general procedures for determining grain size in metals and alloys by estimation of grain size using the comparison method and by calculation of grain size number using the intercept and planimetric methods, specific procedures for austenitic grain size in steels by a range of micrographic methods, and specific procedures for metals and alloys consisting principally of a single phase. Appendices provide explanatory notes on specifying austenitic grain size limits for steel, list etching reagents, and show the standard grain size charts for untwinned grains (flat etch), twinned grain (flat etch), and heavily twinned grains (contrast etch).