A number of crystalline forms of N (2 ((6 (3 (2 6 dichloro 3 5 dimethoxyphenyl) 1 methylureido)pyrimidin 4 yl)amino) 5 (4 ethylpiperazin 1 yl)phenyl)acrylamide are provided. These include a crystalline free base form a crystalline monohydrochloride salt form a crystalline dihydrochloride salt form and a crystalline ethanesulfonate salt form. Methods of making and using crystalline compounds are also provided.