POWERFUL DAYS: The Civil Rights Photography of Charles Moore, <i> text by Michael S. Durham (Stewart, Tabori & Chang: $35; 208 pp.).</i>

They seem so far away now, those days of the civil-rights movement, when what needed to be done seemed so clear, and the enemy, like the police dogs of Birmingham, Ala., and their handlers (above) seemed so well-defined. Charles Moore was a free-lance photographer for Life magazine at the time, and his vivid photographs bring back those days with an immediacy that is a shock to the system. An exceptionally fine record of a heroic episode.