This paper presents the authors view on prosody, information, and models, as well as on the roles of physiology, physics and mathematics in modeling, and describes the theoretical and experimental bases of the command-response model for the mechanisms of F0 contour generation, which has been extensively used in the analysis and synthesis of F0 contours of utterances of various languages. Although the model represents only those factors that are inherent to the control mechanism of F0, it allows one to identify those factors that carry communicative functions of speech as input commands and as parameters of the mechanism.