"The Los Alamos Primer" is a collection of lectures and notes created in 1943 by scientists at the Los Alamos National Laboratory during the Manhattan Project. It served as an educational resource for physicists and engineers working on the development of the first atomic bomb. The primer covers essential topics in nuclear physics, including critical mass, chain reactions, and the principles of fission. The document is significant for its role in shaping the understanding of nuclear weapons technology. It reflects the collaborative efforts of prominent scientists, including J. Robert Oppenheimer and Enrico Fermi, who contributed to the project during a pivotal moment in history.