Moller had begun to think of a professional career rather than staying at home after graduation. She now wished to be called Lillian, a more dignified name for a university graduate she felt, and left home to enroll in graduate school at Columbia University in New York City. Her literature professor Charles Gayley had suggested she study there with Brander Matthews. Graduate enrollment at Columbia was almost half women at the time, but Matthews would not allow them in his classes. Instead, she studied literature with George Edward Woodberry. A lasting influence was her study with the psychologist Edward Thorndike, newly appointed at Columbia. Though she became ill with pleurisy and was brought home by her father, she continued to refer to him in her later work. Back in California, she returned to the University of California in August 1901 to work toward a master's degree in literature. Under the supervision of Gayley, she wrote a thesis on Ben Jonson's play "Bartholomew Fair", and received her master's degree in the spring of 1902.