I had them on my iPod which I downloaded from a LibriVox recording of science fiction short stories.
I particularly liked "Goliah,"
Goliah," in Revolution and Other Essays (1910). A machinist discovers Energon, a new form of energy that enables the ending of war and wage slavery.
I also enjoyed the novel 'The Iron Heel'
He was a product of his times and I think if he had lived longer
would have repudiate social Darwinism and his racist overtones.
Article on his science fiction.
Jack London and Science Fiction
By Clarice Stasz, Ph.D.
"Despite ample, indeed pervasive, evidence in his writings that Jack London had a naturally strong proclivity for fantasy fiction, he has no appreciable reutation today as a practitioner, much less as an examplar, of that for of expression. This fact is particularly odd in light of the proliferation of reprinted fiction works by obscurer literary figures...whose contributions to the genre are, in many instances, patently inferior to London's."
--Dale Walker, The Alien Worlds of Jack London
Jack London was a lifelong fantast. The first money he ever received as a professional writer was for the science fiction story "A Thousand Deaths" published by The Black Cat in 1899. Thirteen of his 188 published short stories and four of his twenty-two novels fall readily into the category, and other stories contain fantastic elements.
London explored numerous styles of science fiction: pre-history, apocalyptic catastrophe, future war, scientific dystopias, technocratic utopias. Running through most stories are the ideas of social evolution, racialism, and anti-capitalism. In some stories, London emphasizes "social science fiction," the problems of society, particularly the exploitation of workers and the materialism of capitalism. By positing extreme cases of social order or disorder, he hopes to convey how human suffering based in economic inequality may be eliminated. In other cases, his imaginary societies were meant to demonstrate the validity of Social Darwinism with its emphasis upon the rise of the superior Anglo-Saxon race.
London's science fiction shows the influence of such horror fantasy writers as Mary Shelley and Edgar Allen Poe, and the popular science fiction writers of the late 19th century, H.G. Wells, Jules Verne, H. Rider Haggard, and Stanley Waterloo. Themes already familiar to turn-of-the-century readers reoccur in London's stories: invisibility, humans turned into beasts, worldwide pestilence, cataclysmic war, indefinable terrors, ghosts, time travel, extra sensory perception (this, before the term was even in the vocabulary).
http://london.sonoma.edu/Essays/scifi.html