This volume assembles 15 complete novels by Mildred A. Wirts (writing as Mildred Benson). A rival to the Nancy Drew series (and created by one of the primary Nancy Drew writers), Penny is a plucky girl reporter whose nose for trouble always leads to a new mystery.

DANGER AT THE DRAWBRIDGE
BEHIND THE GREEN DOOR
CLUE OF THE SILKEN LADDER
THE SECRET PACT
THE CLOCK STRIKES THIRTEEN
THE WISHING WELL
SABOTEURS ON THE RIVER
GHOST BEYOND THE GATE
HOOFBEATS ON THE TURNPIKE
VOICE FROM THE CAVE
GUILT OF THE BRASS THIEVES
SIGNAL IN THE DARK
WHISPERING WALLS
THE CRY AT MIDNIGHT

Note: omitted from this edition are two early Penny Parker novels, which are unavailable due to copyright issues.