Disclosed herein are carbonyl compounds of Formula I, II, or III, and others as described herein. ##STR00001## Also disclosed are methods of treating disease, such as cancer, neurological disorders, including polyglutamine-repeat disorders, anemias, thalassemias, inflammatory conditions, autoimmune diseases and cardiovascular conditions, using the compounds of the invention. In addition, methods of modulating the activity of histone deacetylase (HDAC) are also disclosed.