From the 1870s, the burgeoning number of theatres nationwide as well as the great number of touring attractions made a very complicated business of the scheduling of companies on the road into available theatres while avoiding too great a jump between cities. This gave rise to centralized booking agencies or booking offices in New York. A booking agent had to know railroad schedules as well as the requirements of local theatre managers. Most bookings for the season ahead were negotiated in August when managers from across the nation converged on New York to visit the various booking agencies that were clustered around Fourteenth Street. Until the 1890s, booking agencies were merely the middlemen in charge of distribution of the theatrical product. As managers began to form circuits of theatres to cooperate in getting advantageous bookings, there was a growing tendency toward consolidation of booking and management. It was this situation that gave rise to Klaw & Erlanger, also known as the Theatrical Syndicate, paralleled by Keith-Albee in vaudeville.
The Historical Dictionary of the American Theater. James Fisher.