The Horse and His Boy by C. S. Lewis. This book tells you that things will work out well in the end. That even your mentor doesn't know everything. That small things can save the day. (On the lines of “for want of a nail the kingdom was lost.”) That not everything is the way it seems. Plus it's a well-told tale.
A Wrinkle in Time by Madeleine L'Engle. This was the first sci fi book ever in my life. My teachers read it to us in fourth or fifth grade. We all loved it. I've re-read it many times as an adult and read it aloud to my boys. It's the story of a girl and her little brother who have to go search the universe for their dad who has gotten trapped on another world while doing scientific experiments for the government. In the end love conquers all, but it hurts sometimes on the way.
Moonraker's Bride by Madeleine Brent. This is a story of a Chinese Briton raised in China. She's part of a mission group during the boxer rebellion. The things you learn about China and Victorian England are fascinating. I remember parts of this book well and other parts not at all. It was a favorite of mine and some friends during college.
An Old Captivity by Nevil Shute. This was the first Shute book I ever read. It's about a pilot who turns out to have memories of a place he's never been. But of course no one believes him. You learn a lot about Greenland, Iceland, and early piloting in this book. I also read a lot of Shute's other books because of this one and learned a lot about Australia during the early 20th century.
The Curious Savage by John Patrick. This is a play. I saw it at my high school in tenth grade. I went to every production of it. I think there were four. I searched for the playbook and eventually found it. If I ever find more copies I will buy them too. It's the story of a bunch of people in an insane asylum. But the main character is put there because her relatives want her money. You learn to love the other characters in the asylum. I was struck by the redeeming power of friendship.
This Present Darkness by Frank Peretti. This is a Christian worldview novel in which the need for prayer is made so real that it sent thousands of Christians to their knees. It shows the spiritual side of the world as well as the physical.
Deed of Paksenarrion by Elizabeth Moon. A trilogy in which you learn that sometimes pain and trouble is worthwhile because of what's on the other side. (See Top 10 Fiction blog for more details.)
Her Majesty's Wizard by Christopher Stasheff. I'm a history buff. This is set in an alternative middle ages. I'm an English teacher. The main character is getting his doctorate in English and poetry is magic in this world. I'm a romantic and the boy helps save the girl and her kingdom in this book. And good triumphs over evil. My favorite kind of ending. (See Top 10 Fiction blog for more details.)
The Dragon, the Earl, and the Troll by Gordon A. Dickson. My favorite parts is the morality play, presented to entertain the visitors to the Earl's castle, in which baby Jesus is born and flees to Egypt. The dragons seeking to worship him still makes me cry. I love it when he sings Good King Wencelas and the court is confused. A Mage singing about a Christian King? But then the bishop brings them all together. The world Dickson created is fantastic. I wish he could have written more in this world before he died. But I guess ten books in any series is a goodly amount. (See Top 10 Fiction blog for more details.)
Jubal Sackett by Louis L'Amour. This is one book in a series of books that covers more than a hundred years (more than 200 years) in the lives of various far-flung members of the Sackett family. It is in the middle timewise, but is one of the longer works in the series. L'Amour lived a life of adventure and was a careful researcher so his books are wonderful and accurate. They're fiction of course but that makes them more real in a way. Most things L'Amour wrote make for a fun read. Some are more poignant than others. I have 44 of his Westerns on my shelf. (My brother would tell you some of them are his and I stole them, but that's not the way I remember it.)