To the best of my knowledge, among classical Banach spaces, $c^0,$ c_0,$C[a,b],$L1[a,b],$L_1[a,b],$ $l{\infinite}/c0$ l_{\infty}/c_0$are not dual. 1 To the best of my knowledge, among classical Banach spaces,$c^0,$C[a,b],$L1[a,b],l{\infinite}/c0\$ are not dual.