than Meg but older than Charles Wallace, the twin sons describe themselves as the "squares" of the Murry clan. This changes somewhat when, as teenagers, they are transported to the time immediately preceding the Deluge in Many Waters. In the remaining volumes of the Time Quintet, they are the realists of the family, and tend to be skeptical about Meg and Charles Wallace's accounts and theories about what is happening. In later life, as seen in the O'Keefe series of books, particularly A House Like a Lotus, Sandy is an "anti-corporate" lawyer, and Dennys is a neurosurgeon. Polyhymnia O'Keefe is the protagonist of An Acceptable Time, the fifth book in the Time Quintet. The eldest child of Meg and Calvin, she is born shortly after the events of A Swiftly Tilting Planet. Intelligent and widely traveled, Poly speaks numerous languages. In her first three appearances (The Arm of the Starfish, Dragons in the Waters and A House Like a Lotus), she has not yet settled on a specific career path, but may have found her calling as of the end of An Acceptable Time. Themes The Time Quintet shows themes of love, loss, friendship, loneliness and the triumph of good over evil. L'Engle often borrows elements from the Bible in a way similar to C. S. Lewis, one of her favorite authors. In A Wrinkle in Time, for example, the beautiful creatures of Uriel sing a psalm, and Mrs. Who quotes St. Paul; and angelic characters — the three "Mrs. Ws", the "singular cherubim" Proginoskes, and the seraph Adnarel (who aids just Sandy and Dennys, in “Many Waters”), among others — aid the Murrys and Calvin, but still leave the humans to make their own difficult choices. Another theme which echoes Lewis's work is that phenomena which human perception classifies as "science", "religion" and "magic" are in actuality part of a single seamless reality. Related series L'Engle has written four books featuring the children of Calvin and Meg O'Keefe, especially their eldest daughter, Polyhymnia O'Keefe, and their eldest son, Charles. These are, in order of both publication and character chronology: The Arm of the Starfish (1965) Dragons in the Waters (1976) A House Like a Lotus (1984) An Acceptable Time (1989) These also take place in a Kairos framework, although only The Arm of the Starfish and An Acceptable Time have the characteristic science fantasy elements to any great extent.