Laura Lee Hope was born (sort of) in 1904, when the pseudonym was first used for the first volume of "The Bobbsey Twins." She is not a real person, and in fact, quite often was a man.
Most of the time, the books with her name were written by Howard R. Garis and his wife Lilian Garis.
There are literally hundreds of works using this penname, spanning nearly three decades.