The story is set in ancient times before European traders and missionaries arrived in Polynesia, a group of widely scattered islands in that part of the Pacific Ocean known as the South Seas. In this region, there are typically two kinds of islands—low-lying, coral atolls, and high, mountainous volcanic islands.

A coral atoll is built up over centuries by the skeletons of the coral polyp and rises only a few feet above sea level. It seldom consists of more than a few square miles of land, planted with coconut groves and surrounding a peaceful, inner lagoon. Hikueru, Mafatu's home island, is just such an atoll. His simple village is set against a backdrop of windswept palms amid the spaciousness of the open sea. The volcanic islands of Polynesia are rugged and mountainous, with lush valleys and coastal plans. In this story, Sperry juxtaposes these two types of islands. Mafatu leaves the familiar surroundings of his home, only to be swept away by a ferocious storm to a distant, forbidding, and seemingly deserted volcanic island.

It was the sea that Mafatu feared. He had been surrounded by it ever since he was born.
This remote island has a towering central volcanic peak as well as several deep valleys lush with coconuts, breadfruit, bananas, oranges, and mangos. Wild boars and goats roam freely. Mafatu finds everything he needs for food and shelter on the island, but, frighteningly, he also discovers an ancient shrine where human sacrifices were performed, a sacred and taboo place.

The surrounding sea becomes an almost supernatural, brooding presence during the course of the story. It is a force and a character, an image of the Polynesian sea god Moana himself. On more than one occasion its tumultuous winds and waves terrify Mafatu and nearly destroy his canoe. Its currents direct his journey and cast him ashore. The shifting moods of the sea, whether in turbulent storm or deadly calm, set the tone for each scene.

Sperry's fluid style in Call It Courage suggests the oral recitation of an ancient legend. His words have great dignity, and the narrative proceeds at a stately, measured pace, punctuated by thrilling episodes that move the plot along. Sperry's careful use of Polynesian terms and chants and his knack of personification also contribute to the impression that one is reading a legend.

Personification is a very important aspect of Call It Courage. The sea is Moana, the sea god, a terrifying presence throughout the book. Moana's arms "reach" for Mafatu; his waves "mutter" at the reef and "hiss" with spray; his winds "scream" at the boy. When stranded on the island, the trees "imprison" Mafatu with reaching limbs and "trip" him with roots that twist over the ground. Nature's oppression emphasizes Mafatu's loneliness and fear, but, as his confidence develops, the mood lightens. The tide "hums like a mother's lullaby" after Mafatu has found food and built himself a shelter.

Sperry's artistic abilities are demonstrated by his descriptive passages as well as the illustrations that enhance and complement the text. His perceptions of color, light, and form are reflected in descriptions of sea and sky and tropical island. The sea especially is described as "wastes of leaden water" or a "disk of blazing copper." Sperry also involves the other senses, in addition to sight, in his descriptions. Mafatu feels the "heave and surge of the sea's dark breast." A wave is "a monster, livid and hungry." A land breeze wafts the bittersweet scent of flowers. From the rousing action of the storm to fascinating details of canoe-building or pig-roasting, Sperry is...