Doyle's message was simple and direct: people need to appreciate the short time we have on this Earth, for the end may come at any time, with no warning.
It is a terrifying book about Martians landing on Earth and attacking people with their superior technology. The great cities of the world, including London, fall under the scorching destruction of Martian "heat rays." The human race is on the verge of extinction when, in one of the great plot twists of science fiction, the Martians begin dying out. The invaders have been infected by earth germs, of which they have no natural defense. Humanity is saved by the smallest, humblest of creatures.