1. Melt-quenched nanocrystals (type I nanocrystals) -- 2. Nanocrystals produced by melt quenching at rates close to critical (type II nanocrystals) -- 3. Nanocrystals produced by controlled annealing of the amorphous state (type III nanocrystals) -- 4. Nanocrystals produced by megaplastic deformation of the amorphous state (type IV nanocrystals) -- 5. Application of melt-quenched nanomaterials