This invention pertains to certain carbamic acid compounds of the following formula, which inhibit HDAC (histone deacetylase) activity wherein: A is independently an unsubstituted or substituted bicyclic C9-10heteroaryl group (e.g., quinolinyl; quinoxalinyl; benzoxazolyl; benzothiazolyl); Q is an acid leader group, and is independently an unsubstituted or substituted, saturated or unsaturated C17alkylene group having a backbone length of 4 or less; with the proviso that if A is unsubstituted benzothiazol-2-yl, then Q is an unsaturated group; and with the proviso that if A is unsubstituted quinolin-6-yl, then Q is unsubstituted at the a-position; and with the proviso that A is not benzimidazol-2-yl; and pharmaceutically acceptable salts, solvates, amides, esters, ethers, chemically protected forms, and prodrugs thereof. The present invention also pertains to pharmaceutical compositions comprising such compounds, and the use of such compounds and compositions, both in vitro and in vivo, to inhibit HDAC, and in the treatment of conditions mediated by HDAC, cancer, proliferative conditions, psoriasis, etc.