This chapter describes a procedure for the conditioning of attending behavior in a brain injured hyperactive boy. The data from the experimental and control subject show that it is possible to condition these behaviors in a classroom setting and that the effects generalize from the conditioning period. The observation data offer strong support for the efficacy of behavior modification techniques for the control of the hyperactive child. The data also support the prediction that the effects of the conditioning would generalize to occasions when the apparatus was not being used to control behavior. The complexity of the matrix of stimuli found in the classroom setting, the conditioning of attending behaviors may very well be "slower" than would be the case if the conditioning occurred in a more controlled laboratory setting. However, the classroom procedure should result in greater generalization of effects than would be obtained by conditioning in the more controlled laboratory setting.