Starfleet officer Tania Tobias served on the starships the USS Aldrin and the USS Excalibur (NCC-26517-A), and on the Worlds Within Worlds project, which was supposed to provide an alternative to teraforming.
Tania's father served in Starfleet as Chief engineer aboard the USS Intrepid. He was among the first Starfleet officers to beam down to the site of the Khitomer massacre in the year 2346. (TNG Starfleet Academy (YA Book Series) #1: Worf's First Adventure,Star Trek: The Lost Era novel The Art of the Impossible)
Starfleet Academy
Tania attended Starfleet Academy between the years 2357 and 2361. Soon after arriving at the Academy, she joined a study group that also included Soleta of Vulcan, Zak Kebron of Brikar, Mark McHenry of Earth, and Worf, the first Klingon in Starfleet. (TNG Starfleet Academy (YA Book Series) #1: Worf's First Adventure)
Tania was among the Academy contingent that was sent to the colony on Dantar IV, when the Federation/Klingon co-venture was experiencing problems. When the colony was the victim of a sneak attack, Tania stayed behind on the colony when the evacuation ships hit capacity. (TNG Starfleet Academy (YA Book Series) #2: Line of Fire)
Tania, her squad, and a squadron of Klingon cadets defended the outpost from it's Brikar attackers (The government of Brikar had briefly declared war on the Federation), until re-inforcements arrived in the form of the USS Repulse. (TNG Starfleet Academy (YA Book Series) #3: Survival)
The Aldrin
Tania's first assignment out of the Academy was as an ensign aboard the USS Aldrin. Also on the Aldrin were Academy classmates Worf and Soleta.
Tania got her first taste of command when she was in charge of an away team that was attacked by Romulan smugglers in the year 2363. Tania and Worf were attacked by a Romulan named V'Ret. V'Ret was the first Romulan that Worf had encountered since his family's death on Khitomer, and he did not hesitate to use lethal force. (New Frontier short story: Revelations, No Limits)
Worlds Within Worlds
By the late 2370's, Tania had become attached to the Worlds Within Worlds project, which was designed to offer an alternative to terraforming by using a concept similar to that of a Dyson sphere.
While working on the project, Tania suffered an unexplained mental breakdown that left her prone to having incoherant screaming fits. (New Frontier novel After The Fall)
The Excalibur
Captain Mackenzie Calhoun decided to take a chance on Tania (perhaps because of her history with McHenry, Soleta, and Kebron), and had her assigned to the Excalibur as ops officer. Unbeknownst to Tania, Calhoun instructed the ships computer (in the person of Morgan Primus) to keep a constant watch on her vital signs in case she was to have an episode. (New Frontier novel After The Fall)
Whatever happened at Worlds Within Worlds to cause Tania's episodes, also apparently gave her some sort of extra-perceptionary abilities as well. At Priatia, and in the extra-dimensional, gelatonous realm of the Teuthis and Bolgar, she seemed to be able to sense the comings and goings of the extra-dimensional aliens. (New Frontier novel After The Fall)