Experimental pruning of conifer crops was begun by the Forestry Commission in 1931 and the results of the experiments have been assessed up to date, but the final assessment, that of the pruned timber, still lies in the future. The main purpose of this Bulletin is to indicate the extent of the experimental work done so far and to present its results; but in view of the practical interest at present being shown in the subject in Britain an appraisal is included of the aims of pruning, and the experimental results are used, as far as possible, to make provisional recommendations for forest practice. The foreign literature has been surveyed, but as it is often difficult to relate to British conditions it has been drawn on in making the recommendations only when information from home sources is inadequate. Where the British results disagree markedly with Continental experience, this is indicated.