Roberta Lincoln was a female Human.
In 1968, she was a twenty-year-old resident of New York City. She was five feet seven inches tall, weighed 120 pounds, her hair was tinted honey blonde, and she had two birthmarks; a small mole on her left shoulder and a somewhat larger, star-shaped mole on a portion of her anatomy she preferred not to discuss publicly. She was considered erratic, but also highly intelligent by the Beta 5 computer.
The same year, she was hired as a secretary by Agent 201 and Agent 347, two Humans sent to Earth by aliens to sabotage the launch of an orbital nuclear warhead platform by the USA. Their cover story for Lincoln and others was research for a new encyclopedia. Another agent, named Supervisor 194, Gary Seven, was sent to supervise Lincoln's employer's progress. When he was investigating their disappearance, Lincoln arrived at her workplace, the agents' office. Seven initially mistook her for Agent 201, but quickly realized the truth and told her he was working for the CIA. He also revealed the several technological devices he employed, such as his servo, the Beta 5 computer, exceivers, transporter chamber, and a typewriter that actually typed what was spoken. Though she later learned he was no American and tried to stop him, she then changed her mind and helped him complete his mission. After this success, Captain Kirk remarked that many adventures would lie ahead of Lincoln and Seven. (TOS: "Assignment: Earth")
Lincoln was played by Terri Garr.
In the Eugenics Wars series of novels, Lincoln became known as Agent 368, and worked along with Gary Seven to prevent World War III. In May 1974, Seven and Lincoln discovered the underground laboratory where Khan Noonien Singh and his fellow Augments were created. Lincoln was also sent by Seven to Area 51 in July 1986 to recover a Klingon disruptor and communicator left aboard the USS Enterprise by Pavel Chekov. Despite approaching middle age by the 1990s, Lincoln embarked on various dangerous missions to undermine the efforts of the superhumans in their mad bid to rule the world. Roberta even aided in the procurement of the Botany Bay from Area 51. After Khan and his followers were sent out into space in 1996, Seven retired and left Earth, promoting Roberta to Supervisor in his stead and giving her another cat, Ramses, as her partner. Roberta then recruited another Human, Rain Robinson, to help her, much as Seven had done for her in 1968.