The illustrations in this sweeping tour of the world’s oceans provide more atmosphere than information, and so does the text. Confusingly using the old term “Seven Seas” without explanation to encompass all of Earth’s “oceans, seas, and gulfs,” Vieira takes readers to each ocean, plus the Mediterranean and Caribbean seas, tucking in quick references to the likes of Columbus, Cousteau, and Robert Ballard; the Panama and Suez Canals; oceanic flora, fauna, industry, and pollution, then closing with warnings that, for our “betterment,” we should exploit marine resources more efficiently. Along with this moot idea, Vieira conveys the impression that only European explorers crossed the Indian Ocean, and her blithe claim that “by 1800, all surface areas of the world ocean had been explored” ignores the search for the Northwest Passage, which went on for another half century. The illustrations are a busy mix of insets floating over rolling vistas of waves or deep blue undersea scenes. Perhaps it’s just too vast an array of topics to cover in 32 pages. Titles with a narrower focus, such as G. Brian Karas’s Atlantic (2002) convey a clearer sense of the oceans’ size, diverse biota, and importance. (glossary, maps) (Picture book/nonfiction. 7-9)