Three droll vignettes make up Johnston's (The Iguana Brothers) appealing launch of the Alien & Possum beginner reader series, which introduces two very different pals. After Possum (wearing a spiffy bowler hat) observes a spaceship crash near his tree house, he encounters its passenger: "It was made of many strange things. It made many strange sounds." Alien is also "many colors" while Possum is but one hue: gray. Though the author drums the message home a bit loudly in the first vignette ("Things of all colors can be friends," says Possum), for the most part, the morals are delivered with subtlety and wit, focusing on the ability of friendships to ride out various challenges. In the final story, for instance, Possum falls asleep while Alien reads him a bedtime story and then eats the book ("It was such a good bedtime story I ate it"), but the creature's "electro-perfect memory" enables him to recite the story for Possum when he awakens. DiTerlizzi's (Ted) copious watercolor, gouache and colored pencil illustrations enhance both the humor and the warmth of the caper and help recommend it for readers ready to take a step up from picture books. A springy pace, lively dialogue and Alien's silly sound effects should make this, like Possum's bedtime story, an ideal read-aloud. Ages 6-8. (Sept.)