Notes:

• Month of publication from Locus Index.
• On the Expansion, from the Locus Index "... its most significant addition is a section discussing women SF writers of the period."
• The added section on 'Women's Work' is composed of two extended excerpts, both heavily edited.
  • "From Man's Rights; Or, How Would You Like It?" by Annie Denton Cridge
  • "From Mizora: A Prophecy: A Ms. Found Among the Private Papers of the Princess Vera Zarovitch" by Mary E Bradley Lane
• Please note that in titling the 1995 additions, 'From' was prefixed onto each excerpt title, and separated only by italics typeface. Previous editions denoted heavily excerpted works by prefixing 'From' and then enclosing the original work in double quotes. This stylistic depiction continues in this edition for items previously excerpted. Only the new items omit the quotes.
• Also of note is the fact that the editor chose to introduce both authors together in the essay "Women's Work" instead of individually as in all past editions. There is no separate introductory essay preceding "From Mizora".
• The following titles were removed from this edition (when compared to the 2nd) to make room for the section discussing period women SF writers.
  • Mysterious Disappearances • (1893) • short story by Ambrose Bierce
  • To Whom This May Come • (1889) • short story by Edward Bellamy

There is no prima facie evidence that the introduction was changed when the overall work was 'expanded' in 1995. The introduction makes no reference to the 2nd edition (though it does mention the 1st edition), it makes no allusion to the expansion or the new inclusion of female writers, and finally it makes no use of terms or concepts introduced between 1978 and 1995. Creating a new record for the introduction may have been unnecessary, but is included here until a direct comparison is made between the versions. The essay "Nathaniel Hawthorne and Science Fiction" makes at least one distinct reference to a publication from 1976 (pg. 19, Keywords: A Vocabulary of Culture and Society(1976)), indicating it was revised since 1966, though it isn't clear if it has been revised since 1978. The essay "Herman Melville and Science Fiction" makes at least one distinct reference to events post 1966, (pg. 139 " ... in the era of Harlan Ellison's 1967 'I Have No Mouth, and I Must Scream,'") though it isn't clear if it has been revised since 1978. The essay "Space Travel" indicates it was written several decades after the initial moon landing in 1969, supporting that it was revised especially for the 1995 edition. (pg. 247, "We would go to the moon in 1969, return a few times, and then lose interest for decades.") The essay "Washington Irving and Science Fiction" indicates that it was written well into the late portion of the 20th century by this quote "... have the superweapon sought by the major powers of the late twentieth century, directed energy beams" pg. 250. This seems to be a direct reference to the Strategic Defense Initiative (SDI) and related research programs of the US and USSR in the 1980's. The essay "Beyond the Past" makes reference to at least one post 1966 work (pg. 363 "The Science Fiction of Jack London, 1975"), thought it is unclear if this addition was for the 1978 edition, or the 1995. The essay "Perfect Future" includes several references to items published in the 1980's and 1990's, a positive indication that this essay was updated since the 1966, and 1978 editions.