Capturing learning prerequisites, evaluating learning processes, and assessing learning achievements is the core business of teachers. Meeting the individual needs of all students is both an impossible and the most important task of the teaching profession. The introduction of complex learning objectives in the form of competencies into the curricula does not make this any easier, but it also opens up new opportunities. This volume sheds light on the possibilities and limitations of educational diagnostics to gain a realistic view of what is achievable. Models are presented along which the diagnosis of historical learning can be meaningfully conducted. Finally, numerous examples illustrate how all of this can be implemented in the practice of an overcrowded teaching day.