 In addition to Rivers, the main recurring characters include fellow members of his safari firm, including his partner Chandra Aiyar, camp boss Beauregard Black, and cook Ming.In most instances, the actions of their human clients prove more troublesome than those of the extinct fauna, a theme set in "Faunas", a 1968 poem by de Camp that precedes the stories.An afterword by the author tells how he came to write the series.