The El Dorado Adventure stresses issues which have concerned readers of any era: how characters attain personal growth, and how societies reward good and punish evil. In The El Dorado Adventure, Vesper, Acharro, and de Rochefort attain personal growth; Helvitius and his henchmen are punished and the Chiricans and their friends are rewarded. In recent years, stories in which less sophisticated cultures are exploited, in which environmental issues are explored, in which women are active rather than acted upon, have become common. In The El Dorado Adventure, the Chiricans overcome their exploitation, El Dorado maintains its environmental integrity, and Vesper and the Chirican women act to save themselves and their people.

While it is true that the character of the girl detective is not new to adolescent literature, Vesper is more than a Nancy Drew figure. Rarely does Nancy Drew solve mysteries through her intellect; more...