Most of Henderson's stories emphasize the theme of being different and the dangers therein. They often feature children or
adolescents. Most are part of her series concerning the history of "The People", human beings from a faraway planet who are forced to emigrate to Earth when their home world is destroyed by a natural disaster. Arriving in the late 1800s, and on arrival scattered mostly throughout the
American Southwest, they are set apart by their desire to preserve their home culture, including their religious and spiritual beliefs. Their unusual abilities include
telepathy,
telekinesis,
prophecy, and
healing, which they call the "Designs and Persuasions". The People suppress their unusual abilities as they attempt to integrate into human society. The stories describe groups of The People, as well as lonely isolated individuals, most often as they attempt to find their own communities and remain distinct in a world that does not understand them. This aspect of individuality was a common theme in most of Henderson's writing.
New York Times reviewer
Basil Davenport described the stories as "haunting".
Brian W. Aldiss and
David Wingrove noted that "As a sentimental portrait of the alien, the series out-Simaks
Simak." In a book on early women science fiction writers, Eric Davin noted that all of her stories focus on "the search for community and communication," a theme shared by many women's science fiction stories from the time. A common conflict in Henderson's stories is when a child has unusual powers that a schoolteacher, parent or other caretaker discovers through observation. For example, in "The Last Step" a children's teacher in a future fakes various petty measures to interrupt a children's game on the grounds that they take it too seriously, unaware that the "game" is in fact using
sympathetic magic to save the colony from an upcoming hostile invasion. In another story "The Believing Child," a young daughter of a migrant worker believes so strongly in an
imaginary magic word that its powers come true; she then uses her newfound powers to take revenge on her abusive classmates. Compared to these are more frequent, gentler tales such as "The Anything Box," in which a teacher learns that an unhappy little girl has discovered or created a box in which she can see her heart's desire. The teacher becomes concerned that the child is escaping into the box too frequently (while at the same time craving it for herself). In the end, the teacher allows her to keep the box but warns her not to let herself get lost in it. Henderson mentions mental illness in several tales, including
obsessive-compulsive disorder in "Swept and Garnished", and
agoraphobia in "Incident After". In "One of Them", a woman's latent telepathic powers cause her to lose her identity as she unwittingly probes the minds of her co-workers. In "You Know What, Teacher?" a young girl confides in her teacher of her father's philandering, and of her mother's plan for revenge. == Adaptations in other media ==