This report presents research results obtained in the investigation of deviation control of boreholes in the rotary drilling process. The approach taken in this research is the passive method of placing stabilizers in the bottom-hole assembly to control deviation. Extensive use was made of the drill string mechanics theories of lubinski and woods. Analog, digital, and hybrid solutions to a variety of boundary value problems were investigated to determine the best models for bottom-hole assemblies. Field drilling data were analyzed, and the results obtained from various models were compared with the actual drilling results. Various accomplishments of this work have been published in Bureau of Mines Information Circular 8891.