In 1975, Jack Hetherington and F.D.C. Willard published a paper together in Physical Review Letters. The paper is an influential view into atomic behavior and has been cited multiple times, but only one of its authors is human—F.D.C. Willard is a cat, Atlas Obscura writes. His owner, Hetherington, added the feline (not pictured) as a co-author when he realized that although he was the sole author, he used the plural “we” and “our.” Instead of retyping his entire paper, he simply tacked on his cat Chester, sneakily calling him “F.D.C. Willard” after his species name, Felix domesticus, his actual name, Chester, and the name of the cat’s father, Willard. When the cat was out of the bag, Chester was invited to join the university’s physics department full-time.