Science fiction would not be the same without H. G. Wells (1866-1946). His ideas became an integral part of science fiction culture: time travel (The Time Machine, 1895), human/animal hybrids (The Island of Doctor Moreau, 1896), invisibility (The Invisible Man, 1897), alien invasion (The War of the Worlds, 1898), antigravity (The First Men in the Moon, 1901), and many others. Wells also wrote brilliant short stories that bordered on fantasy: The Sea-Raiders, In the Abyss, The Valley of the Spiders, The Empire of the Ants, etc.
The Time Machine is my favorite. In this novel, an inventor builds a machine that allows him to travel to a distant future. He discovers that humanity evolved into two species: the Eloi, who live in a utopian society above ground, and the Morlocks, who live underground and prey on the Eloi. Wells used this dichotomy as a metaphor for the continuous struggle between the upper class and the underclass. I believe, however, that the main interest of this novel lies not in its socio-political overtones, but in the fascinating vision of evolution it presents. The Time Machine is a reflection on the future of our species and, more generally, the future of life on Earth.