A Swiftly Tilting Planet is a science fiction novel by Madeleine L'Engle, the third book in the Time Quintet. It was first published in 1978 with cover art by Diane Dillon. The book's title is an allusion to the poem "Morning Song of Senlin" by Conrad Aiken. Plot summary The book opens on Thanksgiving evening, 10 years after the events of A Wind in the Door. Meg is now married to Calvin and is expecting their first child. Calvin has become a scientist and is in Britain at a conference; Calvin's mother Branwen Maddox O’Keefe joins Meg's family for Thanksgiving dinner. When they receive the news of impending nuclear war caused by the dictator "Mad Dog Branzillo", Mrs. O'Keefe lays a charge on Charles Wallace of Patrick's Rune, a rhyming prayer of protection inherited from her Irish grandmother. Charles Wallace goes to the star-watching rock, a family haunt, where his recitation summons a winged unicorn named Gaudior, who explains to Charles Wallace that he must prevent nuclear war by traveling through time and telepathically merging with people who lived near the star-watching rock at points in the past. They are threatened along the way by the Echthroi, the antagonists introduced in A Wind in the Door, who now seek to alter history in their favor. Gaudior and Charles Wallace's travels bring them to Harcels, a Native American boy at least 1,000 years in the past; Madoc of Wales, a pre-Columbian trans-oceanic traveler; Brandon Llawcae, a Welsh settler in puritan times; Mrs. O'Keefe's brother Chuck Maddox, during their childhood; and Matthew Maddox, a writer during the American Civil War. Throughout their journey, Meg connects with Charles Wallace from home through "kything", the telepathic communication she learned in A Wind in the Door. Gradually, it is revealed that Branzillo is a descendant of Madoc through all Charles' other alter-egos, and of Madoc's treacherous brother Gwydyr. Ultimately, Charles' manipulation of Branzillo's various ancestors results in the re-union of Madoc's line and the transformation of the present Branzillo into an advocate of peace, to prevent the war. The Rune Resembling St. Patrick's Rune Throughout the story, Charles Wallace invokes this poem to ensure the victory of good. The poem features in several parts of the book, each with slightly different wording or different punctuation; the poem's definite composition is unsure. With Ananda** in this fateful hour,I place all Heaven with its power,And the sun