That Pennterra, as Moffett’s first science-fiction novel, is such an accomplished work no doubt is tribute to her earlier achievements as a poet and critic. The book’s success also stems from the way Moffett can imagine a world so strange yet imbue it with touchingly familiar human problems, emotions, and challenges.
Pennterra, the name given the new planet by its human colonizers, and the overall narrative of the book make it clear that Moffett has an analogy in mind between actual human history and her hypothetical future action. She draws obvious parallels to the colonization of North America by the English. Although the hrossa are culturally and biologically very different from the Native Americans, the territorial and environmental issues are similar. Unlike the early settlers of America, though, the Quakers accept the limitations of the hrossa and adjust their human mentality to that of their neighbors. Moffett does not attempt to disguise the strangeness of the aliens; even the name “hrossa” is not their real name but a name taken from a C. S. Lewis science-fiction novel (Out of the Silent Planet, 1938) also portraying first contact with aliens. The Native American analogy is a way for Quakers to understand their strange situation in familiar terms.
Moffett’s aliens also offer a means of coming to terms with crucial human concerns. This is shown most pivotally in the portrayal of Danny, who is in many ways extraordinary but in other ways a normal boy growing up. Danny takes on the attributes of a human hross. He begins to be able to understand and pronounce the hross language and, far more risky in terms of his identity as a human, to take on aspects of hross sexuality, which is only aroused during certain periods and is, as compared to human sexuality, oriented less toward individual desire and more toward collective happiness. Danny thus represents the cultural cross-fertilization between two species. The humans will never be like the hross: They will always be too individualistic to change completely. Moffett implies, however, that the Quaker settlement will persevere as a successful example of understanding between very different peoples.