A Wind in the Door belongs to Madeleine L'Engle's Time Quartet, of which it is the second installment. Somewhere between cosmic allegory and science fiction, L'Engle has often been compared to writers such as C.S. Lewis and Tolkien because of the Christian tone of her work and the fantastical, imaginative aspect of it. One question that such literature raises, and A Wind in the Door is no exception, concerns the nature of story and whether the theme of a novel ought to contain moralistic or spiritual lessons or arguments. An argument could easily be made that A Wind in the Door, through the development of symbols and plot, argues for the existence of a spiritual realm and the forces of good and evil, specifically in a Christian mode. Although many would argue that such an interpretation is unwarranted or moralistic, the novel seems to be best interpreted with such beliefs in mind.
One of the primary ideas explored by the novel is empathy, which is someone's ability to view another person with charity and appreciation. Consider how Meg Murry is often challenged by her idea of Mr. Jenkins, who throughout the story appears to her in a monstrous facsimile, which suggests that she has a difficult time viewing him correctly or empathetically. Those who have read A Wrinkle in Time might remember his character and the frustration that he represents to Meg during her time as a student.
Meg's journey includes an episode where she is asked to distinguish the real Mr. Jenkins from clones of him. She is able to do this because she realizes that the false images of the man often play into her biases against him, and she comes to realize that regardless of whether Mr. Jenkins has or still is antagonizing her, he still deserves her patience and appreciation, not only because it is right, but also because accessing the type of forgiveness and charity that empathy allows literally helps her to continue on in her journey. The suggestion here is that it is advantageous and beneficial to challenge ourselves to view others with love, even if they haven't earned it, and even when it is difficult to do.
Another important aspect of the story concerns Meg's genius brother, Charles Wallace, whose character is fascinating to analyze. The child's radical intelligence often leaves him misunderstood and ostracized by his peers. And yet, it is a core definition of his character, and also Meg's. The story itself depends on them being able to see into the unseen and correctly understand their relationship to what happens to them, or their fate perhaps, and also their relationship to the cosmic forces of good and evil.
Through the story of Charles Wallace's mitochondrial disease, L'Engle suggests that we as humans are vulnerable to the attack of evil forces, which she depicts through the beings she describes as Echthroi, notably from the Greek word for 'enemies.' When Charles' mother hears about his asthmatic attacks, she suggests that there might be a problem with a part of the mitochondria in his cells called farandolae. Then, as the novel progresses, the protagonists investigate further, finding that it is actual these Echthroi that are afflicting the young man.
This is an interesting comment on the relationship between cosmic, spiritual forces and the material world that constitutes regular reality. L'Engle suggests that even though the disease can be seen through the lens of science, there is also a larger, more mystic aspect to it, which allows disease to be the consequence of evil, and in the end, the children convince a young farandola to grow correctly and fight against the affects of the evil Echthroi, along with their helper, Progo, or Proginoskes.
Overall, the story's explores the ideas of relying on divine (or literally here, extraterrestrial) help in life, being aware that there are unseen forces at work in our minds and bodies, often with insidious intents, but that through love and right thinking, we can have the hope of victory in the strange, frustrating challenges of life.