Judy Bolton: The protagonist of the series, Judy is a bright and resourceful teenager with a knack for detective work. Her curiosity and determination drive the plot as she investigates the strange occurrences surrounding the Yellow Phantom.The Yellow Phantom: The central mystery involves a shadowy figure dressed in yellow who appears to be involved in suspicious activities. The identity and motives of the Yellow Phantom are key to the story's intrigue.Mystery and Suspense: The novel is filled with suspenseful moments as Judy pieces together clues and faces various challenges. The mystery unfolds through a series of investigations and encounters with other characters.Supporting Characters: The story includes Judy's friends, family, and other townspeople who either assist or obstruct her investigation. Their interactions with Judy add depth to the narrative and help advance the plot.