. . "JUVENILE FICTION / Mysteries & Detective Stories." . . "Mystery fiction, American." . . "Adventure stories Young men -- Juvenile fiction Mystery & detective stories." . . "Children's stories." . . "Mystery and detective stories. Juvenile literature." . . "Hardy Boys (Fictitious characters) Juvenile fiction." . . "Teenage boy detectives Fiction." . . "Mystery and detective stories." . . "Swedish language materials." . . "Boy detectives Fiction." . . "FICTION." . . "Teenage boys Juvenile fiction." . . "Grosset & Dunlap." . . "Grosset & Dunlap," . "Detective and mystery stories." . . "Brothers Juvenile fiction." . . . . "Detective and mystery stories"@en . . . . . . . . . "Hardy Boys: Footprints under the window"@en . . . "Footprints Under the Window"@en . . . . "Footprints under the windw" . "The Hardy boys, Footprints under the window" . . "Juvenile works"@en . "Juvenile works" . . . . "Taʻalumat ha-ʻaḳevot mi-taḥat ha-ḥalon" . . . . "De gåtfulla fotspåren"@sv . "De gåtfulla fotspåren" . . . . . . . . . . . . . "The Hardy boys (#12), footprints under the window" . "Juvenile literature" . . . . . . . . . . . . . . "More information to be announced soon on this forthcoming title from Penguin USA."@en . . "Electronic books"@en . . . . . . "Fiction" . . . "Fiction"@en . . . . . . . . "Mystery and detective stories"@en . . . . "Footprints Under the Window #12"@en . . . . "Footprints under the window" . "Footprints under the window"@en . . . "A plot to steal a top-secret instrument vital to the United States space program poses a challenging case for Frank and Joe Hardy. The whereabouts of their famous detective father is a mystery, so Frank and Joe are on their own to foil the plotters." . "A plot to steal a top-secret instrument vital to the United States space program poses a challenging case for Frank and Joe Hardy. The whereabouts of their famous detective father is a mystery, so Frank and Joe are on their own to foil the plotters."@en . . "The Hardy Boys : Footprints under the window"@en . . . "The Hardy boys : Footprints under the window" . . "Frank and Joe attempt to foil a ruthless espionage ring in their effort to sabotage the United States space program."@en . "Frank and Joe attempt to foil a ruthless espionage ring in their effort to sabotage the United States space program." . . . . "The Hardy boys : footprints under the window"@en . . . . "Frank and Joe uncover a plot to steal a vital top-secret instrument of the space program. They go off to jungle-filled islands to uncover a spy ring and recover their father's stolen documents."@en . . . . "The Hardy Boys - Footprints Under the Window 12" . . "Publishers' advertisements" . . . . . "Footprints under the window" . . . . "Footprints under the window"@en . . . "Spy stories"@en . . "Salaperäiset jalanjäljet" . "Hardy boys 12 footprints under the window"@en . "Salaperäiset jalanjäljet"@fi . . . . . . .