A New York Times bestseller, the book deals with genetic engineering and the nature and nurture debate through the subject of identical twins raised apart.

[1] Jeannie Ferrami, Psy.D., is an associate professor and criminality researcher at the fictional Jones Falls University (JFU), an Ivy League school in Baltimore, Maryland.

Lisa works with sympathetic police officer, Lieutenant Michelle Delaware, to create a facial composite of the suspect.

Jeannie's software finds links in medical data and has identified him as the twin of an incarcerated murderer, Dennis Pinker.

He contacts his two partners—Preston Barck and United States Senator Jim Proust—in Genetico, Inc.,[b] a medical research company that heavily funds JFU.

Both men's fathers were in the military when the couples sought fertility treatments at the Aventine Clinic in Philadelphia, Pennsylvania.

Col. Logan runs Jeannie's search on Pentagon computers, yielding three suspects: Henry King, George Dassault, and Harvey Jones.

An eponymous 1997 television film produced by CBS starred Kelly McGillis as Doctor Jean Ferrami, Larry Hagman and Jason Gedrick as Steve Logan, Harvey Jones, and the other clones.

It deals with similar themes as Cloned, which was released only a month prior by NBC, but The Third Twin received greater acclaim.