Sleepovers -- Juvenile fiction. Extraterrestrial beings -- Fiction. Friendship -- Fiction. Science fiction.

Orphans -- Juvenile fiction. Robots -- Juvenile fiction. Rockets (Aeronautics) -- Juvenile fiction. Extraterrestrial beings -- Juvenile fiction. Human-alien encounters -- Juvenile fiction.

Readers (Primary) Extraterrestrial beings -- Juvenile fiction.

Ambassadors -- Fiction. Extraterrestrial beings -- Fiction. Life on other planets -- Fiction. Science fiction.

Extraterrestrial beings -- Juvenile fiction. Books -- Juvenile fiction. Friendship -- Juvenile fiction.

Imagination -- Juvenile fiction. Extraterrestrial beings -- Juvenile fiction. Letters -- Juvenile fiction. Earth (Planet) -- Juvenile fiction.

Extraterrestrial beings -- Juvenile fiction. Earth Day -- Juvenile fiction. Environmentalism -- Juvenile fiction. Extraterrestrial beings -- Fiction. Earth Day -- Fiction.

Extraterrestrial beings -- Juvenile fiction. Sea stories. Water -- Juvenile fiction.

Extraterrestrial beings -- Comic books, strips, etc. Good and evil -- Comic books, strips, etc. Villains -- Comic books, strips, etc. Heroes -- Comic books, strips, etc. Superheroes -- Comic books, strips, etc.

Interstellar travel -- Juvenile fiction. Life on other planets -- Juvenile fiction. Disguise -- Juvenile fiction. Extraterrestrial beings -- Fiction. Friendship -- Fiction.

Xenomorphs (Fictitious characters) -- Juvenile fiction. Extraterrestrial beings -- Juvenile fiction. Human-alien encounters -- Juvenile fiction. Twins -- Juvenile fiction. Space colonies -- Juvenile fiction.

Princesses -- Juvenile fiction. Impersonation -- Juvenile fiction. Kidnapping -- Juvenile fiction. Extraterrestrial beings -- Juvenile fiction. Human-alien encounters -- Juvenile fiction.