The present invention relates to a class of small molecule hydroxamic acid compounds capable of inhibiting histone deacetylases (HDACs). The present invention also relates to methods of preparation of hydroxamic acid HDAC inhibitor compounds of the invention, which are N-substituted-1,2,3,4-tetrahydroisoquinoline hydroxamic acid derivatives, and their incorporation into pharmaceutical compositions and methods of administration. The present invention also relates to N-substituted-1,2,3,4-tetrahydroisoquinoline hydroxamic acid derivatives, which may be prepared as a hydroxamic acid HDAC inhibitor compound library that can be utilized in screening methods known in the art.