(EN) The disclosure is directed to crystalline forms and mixtures thereof of R-fasoracetam. Such crystalline forms include Form II monohydrate R-fasoracetam and the anhydrate form of R-fasoracetam. The disclosure further includes mixtures of the anhydrate form of R-fasoracetam together with one or more of Form I monohydrate R-fasoracetam and Form II monohydrate R-fasoracetam.