Booker, known in Japan as Yusaku Kudo , is Jimmy Kudo's father and husband to Vivian Kudo. He is a famous author of detective stories, and he created the popular character, "Night Baron." He is extremely intelligent, and often had helped the police many times in the past solve cases that no one else were able to solve. His deduction skills are even superior to Jimmy's. He was the one who created the name Phantom Thief Kid from Phantom Thief 1412. It was even hinted that he may have known Toichi Kuroba was the Phantom Thief Kid he was facing.[102] His Japanese voice actor is Hideyuki Tanaka and his English voice actor was Randy Tallman. Booker was later voiced by John Swasey in The Phantom of Baker Street.