In 2366, Lieutenant Commander Shelby was assigned to Starfleet Tactical. She was in charge of Starfleet's tactical analysis and defensive planning for a potential Borg invasion. Under the supervision of Admiral J.P. Hanson, Shelby proved the first who was able to put the project on a productive track. Thereafter, Hanson worked extremely closely with Shelby, spearheading all efforts to develop defenses against the Borg.
When the Federation colony on Jouret IV was destroyed, Shelby and Hanson were dispatched to consult with Jean-Luc Picard and determine whether or not the Borg were responsible. Following confirmation of a Borg presence in Federation space, she stayed aboard the USS Enterprise-D to develop strategies for facing the imminent attack.
Upon hearing that Enterprise first officer William T. Riker had been offered command of the USS Melbourne, Shelby assumed Riker would accept and set her sights on gaining the appointment as Captain Picard's new first officer. However, when she arrived on the Enterprise, she got off on the wrong foot with Riker when she said she intended to become his replacement. She remained at odds with Riker, largely because her fast and loose style clashed strongly with his safe and by-the-book tendencies. Hoping to get an early start on locating evidence of the Borg attack, she led an unauthorized away team to Jouret's surface without receiving approval from Riker beforehand, going over Riker's head to propose combat strategies to Captain Picard himself. Shelby also demonstrated her keen senses when she beat Riker in a poker game by calling his bluff.
Once the Borg attack came, Shelby proved herself to be an extremely capable officer. When Captain Picard was kidnapped by the Borg, she led an away team in an attempt to rescue him. When Riker was granted a promotion to captain, he appointed Shelby to be his first officer and promoted her to commander despite their differences, later noting that they made a good team.
Following the destruction of the Borg cube and Picard's return as captain of the Enterprise, Shelby returned to Starfleet Command to lead the task force assigned to rebuild the fleet following the disastrous Battle of Wolf 359. (TNG: "The Best of Both Worlds", "The Best of Both Worlds, Part II")
|First officers of the starships Enterprise|
|Enterprise NX-01:||Tucker • T'Pol • Sato|
|USS Enterprise:||Pike • Una • Spock • Decker • Saavik (as a trainee) • Thelin|
|USS Enterprise-D:||Riker • Kurn • Shelby • Data • Worf|
|ISS Enterprise NX-01:||Archer|
|ISS Enterprise NCC-1701:||Spock|
|USS Enterprise:||Spock • Kirk|
Shelby was described in the script for "The Best of Both Worlds" as being in her late twenties. She was "very beautiful, energetic, extremely motivated and ambitious." 
Shelby was played by Elizabeth Dennehy.
- "My intent when I wrote the line was that this was indeed the same Shelby from BOBW. I thought it was a cool reference to throw in for the fans, but I had completely forgotten that John Ordover and Co. had very specifically and very politely asked us if we had any intention of ever using this character again and we (including me) had said, "No way – do what you want with her." This very salient fact was pointed out to me after the show had aired and I had a rather sheepish conversation with Paula Block over in licensing and with John via e-mail explaining what had happened. Since I only used Shelby's last name in the episode, you're free to look at this either way – it's really her or it's someone else with the same last name (it's a big fleet, after all)." (AOL chat, 1997)
Shelby reappears in Peter David's novel Vendetta, as first officer of the Excelsior-class starship USS Chekov, serving under Captain Morgan Korsmo. She recounts the battle over Earth to her bridge crew, and is reunited with Riker when the Chekov and Enterprise-D combine forces to halt a new Borg invasion. For some reason, David describes her as having thick red hair, rather than blonde.
David re-used the character as the first officer of the USS Excalibur in the Star Trek: New Frontier series of novels, where her full name was revealed to be Elizabeth Paula Shelby. Later in the New Frontier series, she became captain of the USS Exeter for six months before taking command of the USS Trident (NCC-31347). For more information, please see her New Frontier character entry.
David later wrote passages into a New Frontier novel explaining that there were two unrelated Shelbys in Starfleet, clarifying the discrepancy introduced in "You Are Cordially Invited".
According to the video game Star Trek: Starship Creator, Shelby was born in Lawrence, Kansas to parents Anita and Brian Shelby.