What Is Life? is a non-fiction book on science for the lay reader written by physicist Erwin Schrödinger. One of the discoverers of the structure of DNA, Francis Crick, credited What Is Life? as a theoretical description, before the actual discovery of the structure of DNA (the existence of the molecule had been known since 1869, but its role in reproduction and its helical shape had not even been guessed at this time), of how genetic storage would work and a source for inspiration for the initial research.