Madeline L'Engle Timelines
For those of you confused about L'Engle's time lines, Madeline L'Engle has explained that her works run on two seperate types of time, Chronos, in which the Austin stories exist, and Kairos which is the time line that governs the time-travelling Murrys and O'Keefes.
The Other Side of the Sun seems to be the earliest of the Kairos books. It's a fairly straitforward slice-of-life with romance novel revolving around Simon Renier's grandmother.
A Wrinkle In Time is the first of the "Time Quartet" which details the first adventures of Meg Murry, Calvin O'Keefe and Charles
Wallace in their attempt to save Mr. Murry from the brainwashing power of IT, a malevolent brain.
A Wind in the Door continues the adventures of Calvin, Meg and
Charles Wallace with a stronger theological bent. This is also the book where the unicorn Gaudior first appears.
Many Waters details the adventures of the Murry twins Sandy and
Dennys, who were left out of the other time-travel adventures, as they travel to the time of the biblical Noah and his family and discover some things that aren't in the bible.
A Swiftly Tilting Planet concludes the "Time Quartet". Meg and Calvin, are now married, and Charles Wallace and the unicorn Gaudior are trying to find the connection between the Murry's ancestors the Maddoxs in order to stop a modern-day madman who is threatening the world.
Arm of the Starfish has several crossover elements from the world of the Austins. It's the first of the Polly O'Keefe books although she's extremely young.
Dragons in the Waters continues Polly's adventures. This is the book which reintroduces the Renier family, absent since The Other Side of the Sun . Young Simon Renier befriends Polly on shipboard as they solve a mystery.
In House Like A Lotus Polly travels through Greece prior to attending a confrence on Osia Theola, but is generally preoccupied about her friendship with her elderly patron and the attentions of dimension-traveler Zachary Grey. It also marks the appearance of Queron Reiner, Simon's distant cousin.
An Acceptable Time takes place roughly a year after House Like A Lotus and returns to the environment of A Wrinkle in Time the house of the Murry family. Another time travel tale, though not included in the official "Time Quartet" this book runs along many of the same themes as the other four.
There are so many of her other books I haven't been able to get to yet. Meanwhile, there are some wonderful sites for Madeleine L'Engle already on the web. Check out:
Bonastra
The Tesseract
A Teacher Resource file on L'Engle