Within the past two years a number of services have been offered that make a large central computer available on a time shared basis to anyone who has a terminal. In general these services provide the user with at least one language (usually FORTRAN) that is especially tailored to on-line communications. The following letter describes an application that was programmed in FORTRAN using one of these services. —“To the Editor” by T. E. Hlavac, Jr., Interactive Systems, Inc., Statler Office Building, Boston, Massachusetts 02126.