Dr. Zack Addy (Eric Millegan) was a forensic anthropologist with the Jeffersonian Institute on the television series "Bones." Zack was a child prodigy and a genius as a young adult. He eventually earned two doctorates, one in forensic anthropology and another in applied engineering. His specialty at the Jeffersonian Institute was the analysis of human remains and he was a key member of the investigative team led by Seeley Booth (David Boreanaz).
Zack had a difficult time expressing emotions or making human connections. He prefered to focus on logic and reason as that was the most reliable thing to him. Originally an assistant to Dr. Temperance Brennan (Emily Deschanel), he was initially denied a full position with the Jeffersonian Institute because of his youthful appearance. His colleagues assumed that no one would take him seriously on the witness stand. After team members gave him a makeover to look more professional, he was given the promotion.
Zack's time at the Jeffersonian Institute came to an end when it was discovered that he was acting as the assistant to Gormogon (Lawrence Todd Rosenthal), a cannibal serial killer. Rather than putting him in jail where he would not fare well, the prosecutor in his murder trial worked out a deal with Zack to be declared mentally incompetent and he was placed in a mental institution. He escaped once to help the team with a case, but he returned, albeit unwillingly, shortly thereafter. At this point in the series, he still remains in the institution.
"I'm getting a degree in forensic anthropology; I'm halfway through another in engineering. What are you afraid I'll do? Build a race of criminal robots that'll destroy the Earth?"
"He used a pen, there's a nick on the inferior angle of the mandible. I don't know why he did it. I don't really do why; I just do how."