As the story begins, the unnamed narrator (essentially a fictionalized version of Wells himself) has been invited to an observatory in Ottershaw by a "noted astronomer" named Ogilvy. There he witnesses some sort of explosion on the surface of the planet Mars, one of a series of such events which arouses much interest and debate in the scientific community. A short time later, a "meteor" is seen landing on Horsell Common, near London. The Narrator is among those who go to investigate, whereupon the object is discovered to actually be a space-going cylinder launched from Mars. The cylinder opens, disgorging the the Martians: bulky, tentacled creatures which begin setting up strange machinery in the cylinder's impact crater. A human deputation moves towards the crater waving a white flag of truce only to be incinerated by a laser-like Heat-Ray.
After the attack, the Narrator takes his wife to Leatherhead to stay with relatives until the Martians are killed, but upon returning home, he sees firsthand what the Martians have been assembling: enormous three-legged "fighting machines" armed with both the heat-ray and a chemical weapon: "the Black Smoke". The tripods smash through the British army units now positioned around the crater, and go forth to attack the surrounding human communities. The Narrator meets a fleeing artilleryman, and learns from the soldier that a second cylinder has landed between Woking and Leatherhead, so the narrator is cut off from his wife.
More cylinders land across the English countryside, and a frantic mass evacuation of London begins; among the fleeing swarms of humanity is the narrator's brother, who eventually escapes across the English Channel to France. One of the tripods is destroyed in Shepperton by an artillery battery, and two more are brought down in the Tillingham Bay by the torpedo ram HMS Thunder Child before the vessel is sunk, but soon all organized resistance has been beaten down and the Martians hold sway over much of southern England.
The Narrator becomes trapped in a half-destroyed building overlooking the crater of one of the Martian landing sites and covertly witnesses the Martians close at hand, including their use of captured humans as a food supply through the direct transfusion of their blood. He is not alone; with him is a curate whose intellect and reason have been damaged by the trauma he experienced during the attacks and whose irrational behavior finally causes him to be discovered and dragged away by the Martians. The Narrator barely avoids the same fate, and the Martians eventually abandon their encampment. The Narrator then travels into a deserted London where he discovers that the invaders have abruptly succumbed to terrestrial disease-causing microbes, to which they have no immunity.
In 1898, Italian astronomers had observed natural features on Mars which were improperly translated into English as canals. This fueled the belief that there was some sort of intelligent extraterrestrial life on the planet.
Wells depicts the Martians firing spacecraft to Earth from a giant space gun, a common representation of space travel in the late nineteenth and early twentieth centuries.
Military theorists in the end of the nineteenth century and the beginning of the twentieth had many speculations of building a "fighting machine" or "land dreadnought" (as the Royal Navy called this hypothetical machine on which some experiments were made just prior to the first World War). Wells' concept of the Martian tripods, fast moving and equipped with heat rays and black smoke, represents an ultimate end to these speculations, although Wells also presents less fantastic depiction of the armored fighting vehicle in his short story The Land Ironclads. [1] [2]
On a different field, the book explicitly suggests that the Martians' anatomy may reflect the far future development of mankind itself - i.e. that with the increasing development of machines, the body is largely discarded and what remains is essentially a brain which "wears" a different (mechanical) body for every need, just as humans wear the clothes appropriate to a particular weather or work.
A further development of that idea, that the Martians have given up their stomachs and digestive tracts and instead they subsist by introducing the blood of other creatures into their veins, is sometimes criticised on biological grounds.Manly and Wade Wellamn, who wrote Sherlock Holmes' War of the Worlds which describes the famous detective's adventures during the Martian occupation of London, turned the Martians into simple vampires, who suck and ingest human blood.
H.G. Wells was a strong supporter of the theory of evolution, and saw every species as being engaged in a constant, and often brutal struggle for survival. In the book, the Martian/mankind conflict is portrayed as a similar struggle, but on a larger scale. The book explores the morality inherent in social darwinism, an ideology of some prominence at the time.
The science fiction author Isaac Asimov argued that the book was intended as an indictment of European colonial actions in Africa, Asia, Australasia, and the Americas. In the mindset of the time, European technological superiority was seen as evidence of all-round superiority, and thus Europeans were more qualified to administer colonized regions than their native inhabitants. The novel challenges this perspective by depicting the Martian invasion as unjust, regardless of the Martian technological superiority. Wells himself introduces this theme in the novel's first chapter:
"And before we judge them (the aliens) too harshly, we must remember what ruthless and utter destruction our own species has wrought, not only upon animals, such as the vanished bison and the dodo, but upon its own inferior races. The Tasmanians, in spite of their human likeness, were entirely swept out of existence in a war of extermination waged by European immigrants, in the space of fifty years. Are we such apostles of mercy as to complain if the Martians warred in the same spirit?"—Chapter I, "The Eve of the War."
There is a small autobiographical element to the book: Wells seems to have taken great pleasure in the fictional devastation of locations where he had spent an unhappy childhood.
Animal Rights activist David McKnight, writing in the November 2004 issue of Human and Animal Rights, noted that at least five vegetarians and animal rights activists known to him personally were substantially influenced to take their stance by reading Wells' book, which vividly conveys human beings' horror at becoming in effect the Martians' food animals. He surmises that many other people may have been similarly affected, though it might not have been Wells' intention to propagate vegetarianism. In many passages, an explicit comparison is drawn between the Martians' treatment of humans and the humans' own treatment of cows, rabbits, rats, ants and other creatures which mankind in one way or another treads underfoot.
Many may argue that the book was a message directed to the public saying that the planet is not as safe as it seems. It may act as warning that at any point, something could happen resulting in the downfall of Earth.
Indeed, while there had never been a "War of the Worlds" like the one described by Wells, the real World War which broke out two decades later did have much the psychological and cultural effect which Wells predicted, of shattering the complacency and self-assurance of Nineteenth Century Europe in general and Victorian Britain in particular. And the vivid description of the refugees fleeing London en masse was to be enacted in reality again and again during the cataclysmic wars of the Twentieth Century.
However,there are some questions remaining unanswered:
*The narrator comments that on the fourth or fifth night of his imprisonment in the rubble of the fifth Martian landing, he heard two sets of six distinct reports - sounding like heavy guns firing. No explanation is ever given for this event.
*There is no description of the aftermath of the Southend engagement (Martians vs HMS Thunder Child), so it was not explained if the three supporting ironclads did any damage to the third Martian fighting machine.
*After the Thunder Child incident, no account of the narrator's brother is given, although it can be assumed that he survived to tell the narrator of the events he witnessed. (The original edition, published in Pearson's Magazine, indicates that he married one of his female companions from the London Exodus)
*No information on the landing sites of the eighth, ninth, and tenth Martian invasion ships were given. The only information given is that the site of the seventh landing was "the final and largest" base.
*The narrator's name and his brother's name are never revealed. Some altered versions say he was H. G. Wells himself and that his brother is Wells' brother Frank.