The article is oriented towards the dynamics behind the network of interlocking directorates. In the interorganizational perspective the stability of different types of interlocks/lines between corporations is of strategic importance; in the intraclass perspective, the camers of persons. The article therefore analyzes both. It shows that particularly primary interlocks (interlocks between the corporation in which the multiple director has an inside position and the other corporations in which he has outside positions) as well as multiple interlocks between corporations are considerably more stable than other interlocks. They are most Iikely being used for interorganizational purposes. Most of the interlocks however are generated by a very specific career pattern in which an executive position in a large corporation is almost a prerequisite to obtain many directorships.