In The Rarest of the Rare, Ackerman sets off on journeys that lead to, among other places, the habitats of the golden lion tamarind in the rain forests of Brazil, the monk seals of the Pacific's French Frigate Shoals, and the endearing short-tailed albatross on an almost inaccessible island off Japan, as well as the vital but threatened layover sites of the vastly traveled monarch butterfly. She weaves together her own poetic observations of such invaluable creatures and landscapes with the informed, entertaining, and sometimes quirky or compulsive voices of the men and women who know them best. The result is a book that broadens our horizons by carrying us across them. It sings to us in the voice of that uncommon bird herself, Diane Ackerman.