The manuscript printed below has been written by Prof Jerzy Konorski around 1970, a few years before his death in 1973. The manuscript has not been published before. It was recently discovered in Konorski's papers deposed in the Library of the Nencki Institute of Experimental Biology. In his critical review Konorski debates advantages and shortcomings of the physiological approach of Pavlov and purely behavioristic approaches advocated by Hull and Skinner. He supports close cooperation o behaviorists with neurophysiologists and neuroanatomists, with focus on the investigation of the neural mechanisms underlying behavior. Konorski's ideas concerning the integration of the study of behavior and neurophysiology anticipated contemporary path of neuroscience. Indeed, his approach, which at that time appeared somewhat controversial, is universally accepted by contemporary neuroscientists. By contrast, physiological theories of higher mental functions formulated by Pavlov as well as deliberately anti-physiological approaches of Skinner and Hull have all but disappeared from serious scientific discourse. However, the same problems such as strongly promoted self-importance of some branches of neuroscience, the lack of inter-communication between different branches and resulting lack of integrating ideas appear to emerge anew in each new generation of scientists. (Editors of Acta Neurobiologiae Experimentalis).