In this lecture I try to explain the basic dynamical processes atwork in a radiative zone of a rotating star. In particular, the notionof baroclinicity is thoroughtly discussed. Attention is speciallydirected to the case of circulations and the key role of angular momentumconservation is stressed. The specific part played by viscosity isalso explained. The old approach of Eddington and Sweet is reviewed andcriticized in the light of the seminal papers of Busse (1981) and Zahn (1992).Other examples taken in the recent literature are also presented;finally, I summarize the important points.