Ruth Leavitt

 (called Kate by friends) was one of the best organic chemists in the world and a part of Nuka-Cola Corporation's world class team of organic chemists, the Beverageers.

Background
At some point, Leavitt and Rex Meacham stayed at the Mountainside Bed & Breakfast for a time.

When John-Caleb Bradberton formed a partnership with General Braxton to develop chemical weapons, Lead Beverageer Meacham jumped at the opportunity. Rex Meacham and his team (, Edmund Medford, Kevin Benell) were provided with a cutting edge laboratory built into the foundations of the Nuka-Cola bottling plant. Provided with a dedicated reactor and living quarters, it allowed the Beverageers to work around the clock. Work commenced immediately, although it had numerous failures. Attempts to achieve thermogenesis using radioactive isotopes were challenged by unforeseen side effects on top of simple failure to remain stable. Following experiences with toxic fumes, Beverageers finally found a way to achieve semi-stable isotopes with sample M6N5-UD. However, it was Strontium-90 (sample Q4N7-UM) that was the breakthrough. Liquid at temperatures up to 127 degrees Celsius, stable and inert, but with radioactive thermogenesis capable of activation by manipulating the electron sub-field. Version 0.245 of Q4N7-UM was selected as the basis for further weapons development, as a form of high explosive nitroglycerin. Meacham named the substance Quantum, after the sample identification code, and presented his testing to Braxton and Bradberton. The first accepted it as the basis for the Nuka-Nuke, the latter as a new flavor, Quantum.

Following these three weeks of constant work and laboratory experiments, the Beverageers were given vacation time, while Meacham pored over the data with the General and Bradberton. Project Cobalt was about to yield its first fruit. However, the purpose of the Project and its military applications did not sit well with the best organic chemist on the team,. She repeatedly voiced her concerns to Meacham. He was her mentor and idol, until he decided to have the Beverageers research weapons of mass destruction. To appease her, Meacham placed Dr Leavitt in charge of developing an isotope safe for human consumption. Eventually, she arrived at CE775, which would become the foundation Nuka-Cola Quantum. Her work would result in a drink that would become the Corporation's next biggest seller, as indicated by the pilot program in Washington, D.C. However, as the Beverageers continued to focus on Project Cobalt, Leavitt found it impossible to remain in Nuka-Cola's employ. She openly confronted Meacham in early October and declared that she would tender her resignation at the end of the month. Bradberton was livid. When he learned of her intent, he was furious. By defying his and Meacham's will, Leavitt would wind up blacklisted in the industry. It was a loss for Project Cobalt as well, as Leavitt's expertise was second to none. Dr Edmund Medford was the only other organic chemist qualified enough to pick up the slack and he wasn't even remotely near her league. The other members of the team, particularly Kevin Bennell, considered her choice to be a selfish one in wartime. The eventual fate of Dr Leavitt also entrenched their loyalty.

She continued to work at the Beverageer facility, although she refused to even lift a finger to aid Project Cobalt. The other Beverageers pleaded with her to change her mind. Meacham tried to intimidate her into staying, Bennell tried flattery and appeals to reason, while the meek Dr Medford merely supported his colleague. The arguments continued until October 23, 2077. As the nuclear attack on the United States began, the automated safety systems engaged and the Beverageer lab was locked down. All the Beverageers were trapped within the facility. Isolation and the end of the world as they knew it started to take its toll on the research team. Within a couple of weeks, Dr Medford committed suicide, hanging himself in the dorms. Dr Bennell tried to escape into his work, to cover up the cracks in his composure. Meanwhile, relations between Leavitt and Meacham rapidly deteriorated. Meacham reacted to the end of the world with an obsessive focus on Project Cobalt, convinced that completing it could somehow save America, save it from the Chinese soldiers flooding the mainland. In his mind, Project Cobalt was the key to salvation. The predictable result of his obsession was the shooting of Dr Leavitt when he attempted to open the door leading out of the lab. Outside, he was calm and collected. Inside, Meacham was falling apart, guilt eating away at his murder of a woman he secretly loved.

More weeks passed as he and Bennell tinkered with Project Cobalt, trying to create a stable isotope for use by non-existent troops above ground. Meacham believed that Cobalt could tip the scales of the war. In October 2078, the last of his team finally cracked. Bennell made an escape through the reactor overflow pipe, preferring the risk of death from radioactive exposure to certain insanity. Meacham was psychotic at this point and opened fire on Bennell as he disappeared in the tunnel. Dr Bennell would die of his wounds at the service station in the tunnel, never having reached freedom. Meacham stayed behind, continuing his work and descending into lunacy. In the end, he would finish the Project and perish as he awaited rescue by the military that no longer existed.

Appearances
is mentioned only in the Fallout 4 add-on Nuka-World.