Mary Louise and Josie O'Gorman

Originally published in 1922, fifth of the "Bluebird" novels, written by Frank Baum, author of the Oz books, under the name of Edith Van Dyne. According to Wikipedia: "The Bluebird Books is a series of novels popular with teenage girls in the 1910s and 1920s. The series was begun by L. Frank Baum using his Edith Van Dyne pseudonym... Baum wrote the first four books in the series, possibly with help from his son, Harry Neal Baum, on the third. The fifth book is based on a fragment by Baum and written by an unknown author... The books are concerned with adolescent girl detectives... The Bluebird series began with Mary Louise, originally written as a tribute to Baum's favorite sister, Mary Louise Baum Brewster. Baum's publisher, Reilly & Britton, rejected that manuscript, apparently judging the heroine too independent. Baum wrote a new version of the book; the original manuscript is lost. The title character is Mary Louise Burrows. In the first books of the series, she is a fifteen-year-old girl with unusual maturity (though the other girls in her boarding school find her somewhat priggish). She is suddenly confronted with the fact that her beloved grandfather is suspected of no less a crime than treason against the United States."