The magnetic phase diagram of amorphous FexSc100-x thin films prepared in UHV with 8≤x≤86 shows in the temperature range of 4.2K to RT para-, ferro- and ferrimagnetism as well as (reentrant) spin glass, transversal spin glass and cluster glass states. The different magnetic phases are viewed in correlation to the details of the magnetic interaction and structure. For that purpose it was neccessary to push the experimental and analytic methods to their limits of resolution and sensitivity. This includes a systematic scan of various parameters such as temperature, external field and stochiometry. The results of the magnetometry, Mößbauer spectroscopy, magnetoresistance and EXAFS meassurements mainly fit into the common picture of amorphous magnetic alloys. What is different to e.g. the Fe-Zr system is the fact that Sc actively takes part in the magnetic interaction, especially carring the essential magnetic moment at large Sc concentrations and showing ferromagnetic coupling in this region. The coupling to the Fe moment is antiferromagnetic in nature leading to a ferrimagnetic system at about equal concentration of Fe and Sc. Structural fluctuations are responsable for the formation of clusters of different magnetic character. Only the transition to the transversal spin glass state takes place in the whole sample collectively.