 Under the heading of “structuralism in physics” there are three different but closely related research programs in philosophy of science and, in particular, in philosophy of physics. These programs were initiated by the work of Joseph Sneed, Günther Ludwig, and Erhard Scheibe, respectively, since the begin of the 1970s. For the sake of simplicity we will use these names in order to refer to the three programs, without the intention of ignoring or minimizing the contributions of other scholars. (See the Bibliography.) The term “structuralism” was originally claimed by the Sneed school, see e.g., Balzer and Moulines (1996), but it also appears appropriate to subsume Ludwig’s and Scheibe’s programs under this title because of the striking similarities of the three approaches. The activities of the structuralists have been mainly confined to Europe, especially Germany, and, for whatever reasons, largely ignored in the Anglo-American discussion. 