The principal theme of the novel can be summed up in a few sentences: Life is durable; life is cheap; if men act too much in accordance with the latter, the former will become less true.

The British of Jim’s Shanghai display typical colonialist arrogance. The warring factions of Chinese soldiers kill peasants and themselves with apparent indifference. The Japanese count the individual as negligible in comparison with an outlandish notion of honor in victory and in defeat.

Ballard conveys the inhumanity of these practices with quiet understatement. The public execution of a Communist sympathizer is “this small death.” The understatement strips events to their essence. Beneath war’s clamor are simple truths, simple follies. Jim sees things simplistically, because they are simple.

The controlled use of narrative voice conveys the perceptive mind of the young hero and Ballard’s more considered estimation of events. Increasing in wisdom, Jim remains ingenuous yet perceives the significance of the events that he witnesses.

The book can, for most of its length, be read as a vivid recollection of childhood, but it makes telling points about the conduct of war. Allegiances are, Ballard suggests, formed arbitrarily, and it takes childlike innocence to avoid the prejudice and hate that give rise to war. Many on the “right side” are no more honorable than their aggressors. Jim, his mind muddled by delusion, dreams, illness, and propaganda, nevertheless bares a stark truth: War is folly.

This is not controversial when confined to disparagement of Japanese aggression. Yet Ballard intends to indict others, too. He portrays peoples of several nations and affiliations, all displaying an appetite for violence. Given the opportunity at the end of the war, the captives reek inhumane revenge. Sensing carnage or starvation, one character tells Jim that the greatest threat to the prisoners’ lives would be the end of the war. For Ballard, however, it was the use of atom bombs that best bore out the warning Jim received. It was no salvation, but a step toward ultimate perdition. In Jim’s mind, “the American planes set off powerful premonitions of death.” The effect of the bomb, the narrator says, was “as if the sun blinked, losing heart for a few seconds.” War, and its outcome, are the Empire of the Sun.

Coming of Age
The main focus of Empire of the Sun is Jim's maturation from child to man during World War II. After the war begins and he is separated from his parents, he spends the remainder of the book trying to reunite with them. He learns to survive the brutal conditions he faces in detention and prison camps. As a result of these experiences, he learns important lessons about himself and human nature.

Change and Transformation
As Ballard traces Jim's maturation, he explores the transformations he experiences. The biggest change occurs when Jim is wrenched from his comfortable, privileged life in Shanghai and forced to live, as do the Chinese, with deprivation and the constant threat of death. This experience brings Jim to new levels of self-discovery as he realizes his ingenuity, courage, and resilience in the face of tragedy.

Alienation and Loneliness
Jim must learn to cope with the alienation and loneliness that result when he is separated from his parents. As an only child, Jim had used his imagination to fill lonely days, envisioning himself as a Japanese fighter pilot. His imagination also helped Jim combat the loneliness he suffered after losing his parents.

While in camp, Jim tries to erase his sense of alienation through his interaction with the other prisoners. He considers the prisoners to be almost an extended family, and thus comes to feel a measure of safety while he is interned there. In this way, he tries to create order in a chaotic and dangerous world.

Strength and Weakness
Jim's ability to cope with his harsh surroundings reveals his strength of character and the nature of human adaptability. While others escape through death, Jim resolves to survive. In order to do this, he learns how to eat insects and to ingratiate himself with his captors.

Violence and Cruelty
Jim is able to recognize the capacity for violence and cruelty in others as well as himself. After seeing so much cruelty, Jim comes to understand its causes. For example, "Jim knew that Lieutenant Price would have liked to get him alone and then beat him to death, not because he was cruel, but because only the sight of Jim's agony would clear away all the pain that he himself had endured."

Jim often struggles with his own capacity for cruelty. In order to survive, he obtains extra food, which sometimes means less for others. He also learns how to defend himself against others trying to take food from him. As a result, "few boys of his own age dared to touch" him and "few men." Sometimes stealing food makes him feel guilty and he acknowledges that "parts of his mind and body frequently separated themselves from each other."

Appearances and Reality
By the end of the novel, Jim has let go of his innocent ideas about the nature of war. As a child, he had considered war to be "an heroic adventure filled with scenes of sacrifice and stoicism, of countless acts of bravery" like those detailed on the newsreels he watches and the magazines he reads. By the end of the novel, however, Jim recognizes the devastating reality of war.

War and the consequences of war, death, reverence for life, the relationships between people who will make sacrifices to keep others alive are themes woven into the structure of the main theme—the psychological war waged by Jim. The internees of the prison camp have various agendas, shown in relation to a world Jim creates, the one in which he can survive. The people in Ballard's story move in landscapes that "are symbolic of his characters' psychological state" says DISCovering Authors.

For the foreigners who remain in Shanghai, life becomes a matter of survival rather than a good time. Those who flee the country before the invasion are better off only if they go far enough away with those in the Orient caught up in the struggle. The Japanese are not concerned with the survival of people they put into the camps. They are concerned only that they appear to be concerned. If an internee can survive on the small amount of food available, manage to fight off disease, and live through any attacks on the camp, he or she may survive the war. The death march from the camp to the edge of Shanghai is more than many of the prisoners can survive.

Another consequence of the war is the attitude of the Chinese toward the foreign community. This is illustrated by the amahs at the home of Jim's friends Clifford and Derek. The traditional Chinese amah is a combination housekeeper-child caregiver, often employed by the European families to care for their children. Clifford and Derek and their parents are no longer in residence, and the amahs are stealing furniture from the house. When Jim asks where his friends are, one of the amahs slaps him in the face, hitting him harder than he has ever been hit before. This, coupled with their refusal to talk to him, gives a clear picture of their true feelings for the Europeans. The Japanese are regarded as deliverers more than conquerors by much of the Chinese population during the first few days of the war. This sentiment will change.

In an effort to find his parents, Jim goes to the apartment building where his friend Patrick Maxted lives with his parents. The apartment has been ransacked by the Japanese, but Patrick's model airplanes still hang from the ceiling, representing order among chaos. The next morning Jim talks to the White Russian caretaker from the Shell Company in the building across the street. After showing Jim a picture of two British battleships being sunk by the Japanese, Mr. Guerevitch tries to send Jim after a group of British women and children the Japanese are taking to a camp. Jim refuses to follow because they are prisoners, but begins to understand that the Japanese may be able to win the war. He also suddenly realizes his parents may already be in a camp. He begins to consider the need to find a way to give himself up. An encounter with a Japanese soldier who bends the spokes on the front tire of his bicycle helps him decide that trying to surrender holds as many dangers as living on the street. He wonders how whole armies are able to surrender when he is having such a difficult time.

Part One ends with Jim and his fellow internees finally in a camp. They are to help captured Chinese soldiers build a runway for Japanese bombers to use. Jim knows chances of survival are slim, that they will be worked to death along with the Chinese. Part Two opens three years later, near the end of the war. Ballard puts the beginning and ending in separate boxes, much as a child might do. For Jim, the war itself is not a first hand experience—the beginning and the end provide air raids and other actions that feed his imagination, the middle is routine. Part Three encompasses his last flight, the return to the camp, the rescue by Dr. Ransome, and his return to his parents in Amherst Avenue. Finally, he is to leave China for England. Writing in The Nation, Edward Fox says "the novel ends when Jim is sent by boat to a public school in England, presumably to continue honing his survival skills—the strangest and iciest twist of all." The war with the Japanese may be over, but the psychological war raging inside Jim is far from over.