I wish to express a very deep appreciation of the vision of Chairman W. W. Anderson of Committee D-5. on Coal and Coke, and of the work of Henry F. Hebley, Chairman of Subcommittee XIII on Coal Sampling, and of W. M. Bertholf, Chairman of the Section on Mechanical Sampling. They have done a marvelous job of getting together a group of outstanding papers. As Bertholf says in the introduction to his paper, progress in sampling coal has not been continuous since the publication of E. G. Bailey's classical paper in 1909. There have been considerable periods when all was quiet on the Potomac, as we say in Washington, with not much doing on the theory of coal sampling. Then somebody had a new idea, and interest was renewed. Grumell and Dunningham disturbed a comparatively quiescent period of nearly two decades when they conducted their mathematical and experimental studies in the late twenties. Their work led to the adoption of revised methods for sampling coal by the British Engineering Standards Assn. in the early thirties. ASTM Committee D-5 took up this challenge and appointed Subcommittee XII on Sampling Coal at Coal-Cleaning Plants, under the chairmanship of T. W. Guy, in 1932, and Subcommittee XIII on Mechanical-Sampling and Reduction of Samples, under the chairmanship of J. B. Morrow, in 1934.