Critics of Mark Twain are well acquainted with what have been referred to in various instances as the author’s ambivalent, contradictory or dialectic attitudes. It is in Twain’s approach towards science, technology and the concept of progress itself that this ambivalence is particularly evident. These themes underlie some of Twain’s most famous novels such as The Gilded Age (1873), Adventures of Huckleberry Finn (1885) and A Connecticut Yankee in King Arthur’s Court (1889); however, it is in a series of lesser-known and unpublished sketches, short stories and novels that we find more explicit and creative examinations of the mixed blessings and failures of progress.   This paper will analyze a selection of texts that include “Cannibalism in the Cars” (1867), “Sold to Satan” (1904) and Twain’s original manuscripts for The Mysterious Stranger, with the objective of garnering a more precise perspective on the author’s varying attitudes towards progress which have often been inserted into comfortable linear schemes based on biographical interpretation rather than textual data. Moreover, we will go beyond the convenience of simply presenting Twain’s ambiguity in an attempt to understand the actual point the author is making or at least to explain what lies behind his lack of partisanship in the specific cases of these texts.