The Nature of the Beast - Hardcoverby David G. Mills (Author) Being a correctional officer in a State run prison isn't always considered a lucrative career option, especially for a 19 year old, but it actually can be very fulfilling. Nature of the Beast is the autobiographical account of David G. Mills and his life long career as a correctional officer. David G. Mills worked for 40 years in corrections in two different states. His career as a correctional officer started in 1975 at 19.