A Prologue in genealogy terms is not always in the beginning of a book or musical piece

“The National Home for Disabled Volunteer Soldiers,” Spring 2004, Volume 36, Number 1, by Trevor K. Plante. https://www.archives.gov/publications/prologue/2004/spring/soldiers-home.html
“By Way of Canada: U.S. Records of Immigration Across the U.S. – Canadian Border 1895-1954 (St. Albans Lists), Fall 200, Volume 32, Number 3., by Marian L. Smith. https://www.archives.gov/publications/prologue/2000/fall/us-canada-immigration-records-1.html (Look for other immigration and naturalization articles by Marian who is an expert on these. )
“20^th – Century Veterans’ Service Records. Safe, Secure – and Available,” Spring 2005, Volume 37, Number 1, by Norman Eisenberg. https://www.archives.gov/publications/prologue/2005/spring/spotlight-nprc
“Bridging the Mississippi: The Railroads and Steamboats Clash at the Rock Island Bridge,” Summer 2004, Volume 36, Number 2, by David A. Pfeiffer. https://www.archives.gov/publications/prologue/2004/summer/bridge.html

More found on the NARA website, https://www.archives.gov/

Topical index to Genealogy Notes sections of Prologue https://www.archives.gov/publications/prologue/genealogy-notes#civserv
Archives of Previous issues by year and when published https://www.archives.gov/publications/prologue/index This page also includes the link to indexes for each year it was published back to 1982. That includes subject and author.

Cyndi Ingle who compiles the extensive https://www.cyndislist.com/ has a link to Prologue on the National Archives website under her U.S. National Archives category and directly to many of the specific articles under her a various subject and place categories.