*Includes pictures *Discusses the popular theories behind each mystery *Includes online resources and a bibliography for further reading It was the great mystery of its time and still reads like an episode of "Law and Order" today. In December 1910, a wealthy young woman, thought to be sheltered and above reproach, goes missing shortly after being seen in broad daylight on Fifth Avenue in New York City. The police are called in and begin to question those closest to her, only to have her father, a wealthy manufacturer, insist it must be foul play and that his daughter was on good terms with her entire family. Likewise, he claims that though she was in her mid-20s and in the prime of life, she had no serious romantic attachments. The mother tearfully backs these claims up. While the story was certainly fit for a gripping thriller, it was all too true for Dorothy Arnold and her family. Arnold was a young, well-known socialite whose disappearance was front page news on the East Coast in the early 20th century. By the mid-1930s, Amelia Earhart was one of the most famous women in the world. The American pilot had set a number of altitude and distance records, but she wanted to attempt a circumnavigation of the world. After an ill-fated first attempt, Earhart and Fred Noonan set off on another attempt, creating one of the 20th century's most enduring mysteries. Earhart and Noonan were to land on Howland Island, 1700 miles southwest of Hawaii, but radio transmissions ceased between the plane and authorities on the ground the morning of July 2, 1937. Earhart and Noonan had disappeared, never to be seen again, despite one of the nation's largest and costliest manhunts to date. The mysterious case of actress and dancer Jean Spangler remains one of the most enduring such riddles in the annals of Hollywood crime. The nature of the case itself still evokes a public fascination many decades after her disappearance. Spangler found herself in southern California as a beautiful actress and dancer trying to land movie roles, a common story among the many young women gravitating to American entertainment centers from more conservative towns and cities. As a high-profile celebrity event, Spangler's case does not match the sensationalism attributed to figures such as Amelia Earhart, who sought to circumnavigate the globe by air, the political importance of union boss Jimmy Hoffa, or the fate of Judge Crater, a likely victim of the New York underworld. However, the Spangler story differs in that it carries no dearth of rational possibilities or relevant clues with which to accommodate all of the leading theories. On November 24, 1971, there was little to suggest that the skies above the Pacific Northwest would produce one of the greatest mysteries in American history and a criminal investigation that is still ongoing over 40 years later. However, on the day before Thanksgiving, a man calling himself Dan Cooper boarded Northwest Orient Flight 305 from Portland to Seattle and sat in the rear of the cabin. The identity of the thief who ransomed hostages and then jumped out of a plane with the money that night remains unknown. In fact, his ultimate fate is a mystery, and over 40 years after he jumped out of that plane, the FBI doesn't know much more than it did in 1971. Jimmy Hoffa, once described by Bobby Kennedy as the second most powerful man in America, was a union boss who evoked both respect and fear, and he continues to be a legendary figure who often crops up in conversation and media over 40 years after his disappearance. While it was an open secret that Hoffa had shady connections, the success of his leadership allowed supporters to overlook them. To this day, authorities are still searching for him (or presumably his remains), having been overloaded with false and dead-end leads throughout the decades.