Coral Gardens

by Leni Riefenstahl.Harper & Row, $29.95. These wonderful color photographs of the brilliant inhabitants of coral reefs are almost as exciting as the real thing, and rather more accessible. Ms. Riefenstahl’s brief text describes her adventures in learning to dive at age seventy-one, explains some of the problems of underwater photography, and concludes with an appeal for the protection of reef populations. Translated by Elizabeth Walter.