Keep in mind the vast range of his writings:
+Autobiography
+Children's Fiction
+Adult Fiction
+Nonfiction on Christian Topics
+Poetry
+Philosophy
+Literary History, Theory and Criticism
+Letters
Maybe one of the best resources for gaining a taste of all that broad range would be The Essential C.S. Lewis, edited by Lyle Dorsett.
From the Preface:
This anthology is designed to meet an ever-growing need. It is an introduction to C.S. Lewis and his writing for the person who hears him quoted and sees numerous references to his books. Such men and women are aware of Lewis's reputation and importance, they desire to become acquainted with his work, yet they have no idea where to begin. It is also for those who have read one or two of his books, but have no idea what to read next. Finally, this volume attempts to represent essential Lewis for those whose time or resources are limited.That sounds like you and me!
Let me close with two of my favorite excerpts from The Chronicles of Narnia:
from The Lion, the Witch and the Wardrobe
"Aslan a man!" said Mr. Beaver sternly. "Certainly not. I tell you he is a King of the wood and the son of the great Emperor-Beyond-the-Sea. Don't you know who is the King of the Beasts? Aslan is a lion - the Lion, the great Lion."from The Last Battle
"Ooh!" said Susan, "I'd thought he was a man. Is he - quite safe? I shall feel rather nervous about meeting a lion."
"That you will, dearie, and no mistake," said Mrs. Beaver, "if there's anyone who can appear before Aslan without their knees knocking, they're either braver than most or just silly."
"Then he isn't safe?" said Lucy.
"Safe?" said Mr. Beaver. "Don't you hear what Mrs. Beaver tells you? Who said anything about safe? 'Course he isn't safe. But he's good. He's the King, I tell you."
It was the Unicorn who summed up what everyone was feeling. He stamped his right fore-hoof on the ground and neighed and then cried:And finally one last selection from Lewis himself, written a few weeks before he died, from Letters to Children:
"I have come home at last! This is my real country! I belong here. This is the land I have been looking for all my life, though I never knew it till now. The reason why we loved the old Narnia is it sometimes looked like this. Bree-hee-hee! Come further up, come further in!".....
.....And for us this is the end of all the stories, and we can most truly say that they all lived happily ever after. But for them it was only the beginning of the real story. All their life in this world and all their adventures in Narnia had only been the cover and the title page: now at last they were beginning Chapter One of the Great Story which no one on earth had read: which goes on for ever: in which every chapter is better than the one before.
The Kilns, Kiln Lane
Headington Quarry,
Oxford.
26th October 1963
Dear Ruth...,
Many thanks for your kind letter, and it was very good of you to write and tell me that you like my books; and what a very good letter you write for your age!
If you continue to love Jesus, nothing much can go wrong with you, and I hope you may always do so. I'm thankful that you realized [the] "hidden story" in the Narnian books. It is odd, children nearly always do, grown-ups hardly ever.
I'm afraid the Narnian series has come to an end, and am sorry to tell you that you can expect no more.
God bless you.
yours sincerely,
C.S. Lewis
