An thorough and accessible biography of Dr. Katalin Kariko, winner of the 2023 Nobel Prize in Physiology or Medicine, whose hard work pioneering mRNA research led to the COVID-19 vaccines. Long before the COVID-19 pandemic, scientist Katalin Kariko was one of the few people who believed in the potential of mRNA to help cells fight off disease. Breakthrough chronicles Kariko's relentless pursuit of knowledge and dedication to helping people, depicting her as an inspirational figure for readers interested in science. The book contextualizes Kariko's work within her upbringing in a small village in rural Hungary, the discrimination she faced as an immigrant and woman scientist, and the COVID-19 pandemic. Accessible descriptions of the science behind mRNA support the main narrative, and profiles of other significant figures in the development of the mRNA vaccine illustrate how scientific achievement is never earned alone.