Ancient Rome and Pompeii :：a nonfiction companion to Vacation under the volcano / "A nonfiction companion to Vacation under the Volcano" Ancient Greece and the Olympics :：a nonfiction companion to Hour of the Olympics / Ancient Greece and the Olympics：a nonfiction companion to Hour of the Olympics Rain forests：a nonfiction companion to Afternoon on the Amazon Knights and castles：a nonfiction companion to the knight at dawn Sea monsters /：a nonfiction companion to Dark day in the deep sea. Titanic：a nonfiction companion to Tonight on the Titanic