What contribution can social work in schools make to ensure that diversity, in terms of the different resources and potentials of children and adolescents, is recognized and promoted in everyday school life, that internal exclusion is avoided, and that equal participation in education for all is pursued? This question is addressed in the present anthology. All previously published international comparative studies on school performance conclude that educational success is heavily dependent on the socioeconomic background of children and adolescents within the German education system. Selection mechanisms can be identified in the education system that lead to children and adolescents not receiving adequate support, resulting in failed educational careers. At the same time, schools are shaped by cultural and social heterogeneity, which all participants must engage with.