If you're very young, your secret pleasure may come from two friends in children's books: Frog and Toad.
The two amphibian friends go sledding, look for spring, eat chocolate ice cream cones and are completely devoted to each other.
They're the creation of the late writer and illustrator Arnold Lobel, who led them through small adventures in four books during the 1970s.
Lobel died in 1987. But now, there's a new addition to the world of Frog and Toad, a collection of 10 rhyming stories called The Frogs and Toads All Sang.
These stories and pictures were drawn before the Frog and Toad books that were previously published. The stories were gifts written and drawn in black and white by Lobel and given to friends.
The newly published books have color added by his daughter, Adrianne Lobel. She tells NPR's Melissa Block that the manuscript turned up last year at an estate auction.
"In a box they found these three beautifully bound pamphlets that my father had handwritten and illustrated with little pencil, thumbnail sketches. These books were poems about frogs and toads," she says.
It was a big surprise to find them. Her father, she says, must have written them in the mid- or late 1960s in secret. Before she found them, she says, she had always credited herself as the person who instructed her father as to the difference between frogs and toads.
"I was in Vermont one summer. We used to rent houses. And I came in with a toad in my hand. And he said, 'What a nice frog you have there.' And I said, 'No, no, no, no, no. This is not a frog; this is a toad.' And then, a year later, the first Frog and Toad book came out."
She says, in adding color to the black and white paintings in the manuscripts, she remembered something her father used to tell her: Don't be afraid to color out of the lines.
"So, of course, on these illustrations, I worked with a huge brush and with very brilliant Dr. Martin's dyes and a lot of water, and the sloppier I was, in a controlled way, the happier I was with the illustrations," she says. "I wanted each illustration to have even more form than the original drawings and a lot of light, and, I think, for the most part, I did succeed in doing that."