Who is Emil Larkin from Jailbird and what is their importance?

Larkin is a fellow inmate of Starbuck's in Finletter Prison, a fellow participant in the Watergate affair. There is little evidence to suggest that Larkin is a real person (in the way that Nixon, for example, is a real person). There are indications, however, that Larkin at least is based on a real person - G. Gordon Liddy, a real-life Watergate conspirator who converted to evangelical Christianity while in prison.