Rejected by Nature as too speculative, Enrico Fermi's "Attempt At a Theory of Beta Rays" was published in Italian and German journals. It introduced key concepts such as derivation of the shape of the electron energy spectrum, the expression of the decay constant, the selection rules for scalar and vector interactions, and the expression of the “ft” values.

Wolfgang Pauli postulated the existence of a neutral, light-weight particle that could save the fundamental law of the conservation of energy. Enrico Fermi later named it "neutrino" and gave it a central role in the theory of beta decay. It would be 25 years before neutrinos were confirmed experimentally.

Wu received her elementary education at a school for girls founded by her father, then was sent to a boarding school in Suzhou for preparatory studies. Her teachers kindled her growing interest in science.

Rustad was the second of three children of Louis Lars Rustad and Edith E. Swanson. He was baptized at the Christ Lutheran Church in St. Paul, Minnesota.

Ruby was the second child of second-generation Russian Jewish parents from New York City and Albany. His father was a traveling salesman and marketing innovator in the silver ware industry.. 

Wu was born in the town of Liuhe, Taicang in Jiangsu province, China, into a family that highly valued education. Her father, an engineer who encouraged women's equality, was a notable activist during the 1911 revolution that modernized the country.

Rutherford et al (1911) determine that a tiny, plus-charged nucleus is at the core of the atom with electrons orbiting in mostly empty space. Marsden (1913) introduces the concept of the isotope to explain elemental variations. First atomic transformations achieved by alpha particle bombardment (1919). 

New types of radiation observed by Roentgen (x-rays, 1895) and Becquerel (beta rays, 1898) opened study of atomic transformation via radioactive decay. Key principles are established by M. Curie (process of beta decay, 1902) and Rutherford (principle of the half life, 1904). 

Contradictory results clouded the theoretical picture in beta decay until an experimental refinement by Wu and Albert demonstrated agreement with the Fermi theory. Their breakthrough involved using a soap bubble process to create a monoatomic layer of radioactive copper.