A sampling technique is defined as introducing control into the selection ofnout ofNsampling units when it increases the probabilities of selection for preferred combinations of units (and decreases the probabilities for non-preferred combinations). Methods used in the past have by no means exhausted the possibilities of controlled selection, however. Procedures are developed by which the probabilities of selection for preferred combinations are sharply increased and the theoretical basis for the methods is stated. The methods are applied to a specific problem and the procedures are described in detail. It it found that as a result the variances of estimates for several important items are reduced as compared with the corresponding variances for stratified random sampling.