Abstract
In this paper we review the theoretical problems due to the pinning of vortices. We emphasize the difficulty of making a link between the elementary pinning force between an isolated vortex and a pinning center with the measured pinning force. We show how to define experimentally the pinning force which permit a theoretical study and we calculate it. Far from Hc2, we get Webb's results. Finally, we briefly review calculations of the elementary pinning force