The Time Machine
Wells, H. G. The Time Machine. New York: Henry Holt, 1895. London: William Heinemann, MDCCCXCV (sic). See Currey 524-25 for discussion of bibliographic matters (which are complex and still controversial). Frequently rpt., including H. G. Wells: The Time Machine [and] War of the Worlds: A Critical Edition. Frank D. McConnell, ed. New York: Oxford UP, 1977.
Possibly the first influential work with an inhabited, mechanized underworld — contrasted with an apparently ideal green world on the surface. (The Underworld, traditionally, is the womb of the Great Mother; mechanizing the Underworld is a radical displacement of a central archetype.)
Note also the time machine itself, probably the second in Western literature, after The Anacronópete, and highly influential.
Discussed for its racial aspects in Isiah Lavender's Race in American Science Fiction.
From "The Posthuman Future of Man," which see:
In many respects, H. G. Wells's The Time Machine can be regarded as the apotheosis of the mechanical image of man as subscribed to by nineteenth-century technoscience. [...] The product of the traveler-narrator's technical inventiveness issues from a productive symbiosis of science and craft in the nineteenth century, the foremost aim of which is to subject nature and to advance technical progress. (p. 145)
Old Time Radio: Science Fiction (p. 40) notes a radio broadcast adaptation of Time Machine on CBS-Radio Escape 22 October 1950: Irvin Rabitch, script; Norman MacDonnell, producer and director.
RDE, finishing link added, 13Aug20, expanded 9Jun21, 24Jan23, 29Mar23, 16Aug23