In the November 1943 issue of the journal Genetics, Salvador Luria and Max Delbrück settled a long-running but arcane debate among bacteriologists. The original paper is freely downloadable, and is an amazing document to read today. There’s a delightful innocence in the simplicity of the experimental design, the lengthy explication of the theory behind the work, and the humbleness of the authors’ conclusions. There is no hint that the paper is describing the dawn of molecular biology, a field that would revolutionize humanity’s relationship with nature in ways that are still unfolding 75 years later.