Robert Arthur Jr. (1909-1969) was an American writer and editor who made significant contributions to crime and speculative fiction. Born in the Philippines, he pursued higher education at the College of William & Mary and the University of Michigan, earning degrees in English and Journalism. Arthur's career spanned various media, including prolific work in radio drama and television. He was a key figure behind "The Mysterious Traveler" radio series, earning multiple Edgar Awards for his contributions. His writing also appeared in numerous genre magazines. Arthur is perhaps best known for creating "The Three Investigators" series for young adults, initially published under the "Alfred Hitchcock and the Three Investigators" banner due to his role as ghost-editor for Hitchcock anthologies. He also penned scripts for television shows and compiled several anthologies, many under the "Alfred Hitchcock Presents" imprint.

Robert Arthur Jr. was born in 1909 on Corregidor Island in the Philippines, where his father was stationed with the U.S. Army. His early years were marked by frequent relocations due to his father's military career. Despite being accepted into West Point, Arthur chose an academic path, enrolling at the College of William & Mary in 1926. He later transferred to the University of Michigan, where he completed his Bachelor of Arts in English in 1930. He continued his studies at the same university, earning a Master of Arts in Journalism in 1932, after which he worked as an editor.

Arthur's writing was featured in a wide array of popular magazines, including The Magazine of Fantasy and Science Fiction, Ellery Queen's Mystery Magazine, and Black Mask. He also penned numerous mystery novels aimed at younger audiences. His most enduring creation is "The Three Investigators," a popular series of young adult novels. Initially, these books were presented as "Alfred Hitchcock and the Three Investigators," reflecting Arthur's extensive work as a ghost-editor for most of the "Hitchcock" anthologies published by Random House. In 1959, Arthur relocated to Hollywood, where he began writing and editing screenplays and scripts for television programs.

A significant portion of Robert Arthur Jr.'s career was dedicated to radio drama. Alongside his writing partner David Kogan, Arthur received three Edgar Awards from the Mystery Writers of America for his radio work. These accolades included two awards for "best radio drama" – one in 1950 for "Murder by Experts" and another in 1953 for "The Mysterious Traveler." He also received an award in 1951 for "outstanding achievement in producing, directing and writing radio mystery shows," recognizing his comprehensive involvement in both "Murder by Experts" and "The Mysterious Traveler." Arthur also contributed to other radio series such as "Dark Destiny" and "Adventure Into Fear."