The Cepheid Variable Science Fiction Club came into being in the period 1967 – 1969, the result of science fiction fans gradually coming together and organizing. Following a trip to the World Science Fiction Convention in 1967, Annette Bristol and Danielle Dabbs started the first known science fiction club, with Annette the President, Dabbs the secretary, and John Moffitt as vice-president. The club was pictured in the 1968 Aggieland, with officers listed there. The club was sponsored by the English Department, with two English professors as advisors.

In 1969, Cepheid was a part of "Science Fiction Week," the immediate precursor to AggieCon. "Science Fiction Week" featured Harlan Ellison as special guest, joined by Chad Oliver. Ellison spoke to many (perhaps 30) English classes. His visit was culminated by a meal function at the Ramada Inn, recalled by many for a "food fight" among other things. Cepheid was dissolved as a club, in part due to issues with the hotel.

In 1970, Gary Mattingly reorganized Cepheid Variable and became the second President of the club. Cepheid held a convention in the spring, referred to as a "comics and trade convention" in the Bryan Eagle. In 1971/1972, the first constitution of the club was written.

In April, 1972, the first named convention, AggieCon III was staged by Cepheid Variable. AggieCon is the most visible aspect of the Cepheid Variable Club, and has been continuously produced from 1969 to 2005 at this writing. It has been a very successful convention, and holds the distinction of being the longest continuously operating convention completely run by a student group. Cepheid Variable and AggieCon have many alumni in science fiction. Among them are Steve Gould, author; Noel Wolfman, currently a production supervisor for Dreamworks; Jayme Lynn Blaschke, author and editor; Martha Wells, author; and Brad Foster, Hugo winning artist.

Over the years, AggieCon has hosted many important names in the science fiction and fantasy field as Guests of Honor. Among them are: Harlan Ellison, Anne McCaffery, Fred Pohl, Damon Knight, Kate Wilhelm, Theodore Sturgeon, Bob Tucker, Chad Oliver, Poul Anderson, Jack Williamson, Kelly Freas, Joe Haldeman, C. J. Cherryh, Roger Zelazny, Harry Harrison, L. Sprague de Camp, Catherine de Camp, John Varley, George R. R. Martin, Ben Bova, Spider Robinson, Jeanne Robinson, Walter Koenig, Fred Saberhagen, Lynn Abbey, David Drake, Michael Moorcock, Julius Schwartz, Greg Bear, Charles De Lint, Lois McMaster Bujold, Margaret Weis, Dave Wolverton, Jim Baen, Nancy A. Collins, Joe Lansdale, Bruce Sterling, Robert Asprin, Terry Pratchett, Charles de Lint, Neil Gaiman, Todd McCaffrey, and Elizabeth Moon.

AggieCon has also included numerous Texas authors as guests, many who have gone on to establish international reputations. AggieCon has been an important venue for Texas authors to promote their works, and regional guests have included authors such as Neal Barrett, Jr., Rachel Caine, Lillian Stewart Carl, Bill Crider, Carol Nelson Douglas, Steve Gould, Rory Harper, Katherine E. Kimbriel, Tom Knowles, Joe Lansdale, Justin Leiber, Ardath Mayhar, Laura Mixon, Warren Norwood, Chad Oliver, George W. Proctor, Tom Reamy, Nina Romberg, Lewis Shiner, Bruce Sterling, Lisa Tuttle, Steven Utley, Howard Waldrop, Martha Wells, along with many others.

This list of science fiction personalities is impressive, and has afforded the students of Texas A&M University the opportunity to hear them speak, visit with them, and become acquainted with their writings. Few events on this campus have exposed students to as many literary figures than has AggieCon.

Early in the existence of AggieCon, program booklets became standard fare. The first program book in the collection comes from AggieCon 7, 1976. The contents of the program books vary, but typically they include brief biographies and photos of guests, descriptions of movies, lists of committee members, schedules of events, and illustrations by guests or committee members. Bill Page did a brief history of AggieCon in the AggieCon XX Program Book. He noted that AggieCons II and III were small, with no Guest of Honor, and that "AggieCon III was the first to be called AggieCon." Most of the stories of AggieCon remain to be told. The infamous food fight of the 1969 event, featuring Harlan Ellison, remains legendary, but mostly unrecorded, as do most of the events of the following years.

AggieCon evolved over the years, to become a well-regarded event featuring books and authors, soon adding artists, and then later to feature media programming and stars more prominently, and then back toward a more print-oriented convention.

Cepheid Variable and AggieCon served as the focal point for many activities. Science fiction and fantasy has always been the core around which the club and conventions were built. Additional interests reflected in club and convention activities included: motion picture screenings, gaming, comics fandom, anime and manga, music (including performances by "Los Blues Guys"), filk singing, the SCA (Society for Creative Anacronism), fantasy weapons (especially swords and knives), costuming, and others.

While there is no official connection between AggieCon and the University Library, the two organizations have complemented each other for years. The Cushing Library Science Fiction and Fantasy Research Collection has been a tour site for many years, introducing authors and fans to the existence of the collection, and affording them the opportunity to see items they have never had the opportunity of view. Those contacts have fostered later research visits to the collection, and have resulted in donations to the collection.

The convention struggled for years as an independent effort. In the fall of 1972, Cepheid Variable became a sub-committee of the Contemporary Arts Committee of the MSC. A year or two later, it became an MSC Committee.

The successful acceptance of the group as an MSC Committee provide funding, guaranteed access to MSC space for the convention and programming, fiscal handling support, and advice and guidance from the Memorial Student Center administration and staff. The latter was regarded with a jaundiced eye by Cepheids, but, it should be noted, they diligently listened and heeded the advice of the MSC administrators – occasionally. In 2004, "budget restrictions" were cited as the reason the MSC dropped Cepheid Variable from MSC Committee status and support. The student organizers continued their work, and successfully produced AggieCon 35 in 2005.