Polymorphic forms of 3- (4-amino-1-oxo-1,3 dihydro-isonidol-2-yl) -piperidine-1,6-dione

Disclosed polymorphic forms of 3- (4-amino-1-oxo-1,3-dihydro-isoindol-2-yl) -piperidine-2,6-dione. The present invention further polymorphic forms, methods of making the polymorphic forms and their use.