Which children's novel introduced the Banks family of 17 Cherry Tree Lane?

Mary Poppins is a series of eight children's books written by P. L. Travers and published over the period 1934 to 1988. Mary Shepard was the illustrator throughout the series.

The books centre on the magical English nanny Mary Poppins, who is blown by the East wind to Number 17 Cherry Tree Lane, London, and into the Banks' household to care for their children. Encounters with pavement-painters and shopkeepers, and various adventures ensue, until Mary Poppins abruptly leaves (i.e., "pops-out"). Only the first three of the eight books feature Mary Poppins arriving and leaving. The later five books recount previously unrecorded adventures from her original three visits. As P. L. Travers explains in her introduction to Mary Poppins in the Park, "She cannot forever arrive and depart."

The books were adapted by Walt Disney in into a musical film titled Mary Poppins (1964), starring Julie Andrews and Dick Van Dyke. In 2004, Disney Theatrical in collaboration with Cameron Mackintosh (who had previously acquired the stage rights from Travers) produced a stage musical also called Mary Poppins in London's West End theatre. The stage musical was transferred to Broadway, in New York, in 2006, where it ran until its closing on 3 March 2013.