The New York City Public Library was the location of the first ghost encounter. It is located at the intersection of Fifth Avenue and West 42nd Street in downtown New York City.
After receiving a phone call from Roger Delacorte, Egon Spengler and Ray Stantz went to the library to check P.K.E. levels and investigate. After the P.K.E. levels maxed out the P.K.E. Meter, Dr. Stantz returned to Columbia University to pick up some other equipment and get Dr. Venkman to join the team. Once the team assembled at the library, they interviewed Alice the librarian, a recent victim of the ghost, and went down to the stacks to look for the specter she described. They encountered the Library Ghost and tried to make contact with it. The experience later gave Dr. Stantz and Dr. Spengler some impetus to develop a proton storage facility for indefinite incarceration of spirits.