How about a kid's most immediate fears? Getting lost, losing a parent, or perhaps finding out that your parents aren't really your parents after all.
With the classic children's book Are You My Mother? P. D. Eastman has tapped into every single one of these fears, all in clear, simple language, that, as the cover boasts, your child can read all by himself.
In the beginning of the book, the mother bird realizes her baby is about to hatch, so she goes off to find food. The baby thus enters the world cold, alone, and abandoned, and promptly falls out of the nest. He asks a kitten if it is his mother, but "the kitten just looked and looked." This is perhaps the most implausible aspect of a book that contains talking animals, a robin sporting a polka-dot kerchief, and an excavator gentle enough to transport a baby bird. I cannot imagine any cat that would "just look and look" should it be approached by a helpless baby bird fallen out of its nest. Just saying.
Over the course of the next few pages, the baby bird is devastated to learn that a hen, a dog, a cow, a boat, a plane, and a "snort" (excavator) are not its mother. The scene where he futilely chases after the airplane in an image reminiscent of a reverse-but-equally-desperate North by Northwest moment is particularly poignant.
Eventually, the baby bird meets and recognizes his mother (he knows it is she because she is "a bird," although I'm not certain how that reasoning disqualifies the hen), and the reader learns that phenotypical biology trumps all, even though she is a neglectful parent who abandoned her child in the first hour of life and maybe her offspring could have been much better off as the adopted son of the cow.
Make sure your child knows that the excavator is not actually called a "snort." Otherwise, when your hyperactive, jittery offspring pleads loudly in the toy store that he really needs a "snort," someone might call Child Protective Services.
Eastman, P. D. Are You My Mother? New York: Random House, 1960.
Watch the story told on YouTube.
Are You My Mother?