School segregation continues to be understood as legitimate in Germany. To explain why, we chart the development of the learning disability discourse and the special education profession, providing insights into the ongoing expansion of segregated special schooling. The discourse analysis of articles published between 1908 and 2004 in the special education professional association journal, "Zeitschrift fur Heilpadagogik," uncovers the knowledge base of special education that led to the rise of its main category, "learning disability," and school type, the support school (then: "Hilfsschule," now: "Forderschule"). Despite critical junctures over the twentieth century, special education's dominant discourse and school structures exhibit remarkable continuity. We find professional authority with respect to "learning disability" is a key factor in the persistence and continued growth of segregated special education. Scientific discourse continues to legitimate the classification of pupils as "learning disabled" and their subsequent allocation to segregated schools. (Contains 1 note.)