Several protein misfolding diseases are associated with the conversion of native proteins into ordered protein aggregates known as amyloid. Studies of amyloid assemblies have indicated that non-native proteins are responsible for initiating aggregation in vitro and in vivo. Despite the importance of these species for understanding amyloid disease, the structural and dynamic features of amyloidogenic intermediates and the molecular details of how they aggregate remain elusive. This review focuses on recent advances in developing a molecular description of the folding and aggregation mechanisms of the human amyloidogenic protein β2-microglobulin under physiologically relevant conditions. In particular, the structural and dynamic properties of the non-native folding intermediate IT and its role in the initiation of fibrillation and the development of dialysis-related amyloidosis are discussed.