What is the significance of the title, The Empty Chair?

The title of the novel refers to a psychoanalytic technique used for "understand ing certain types of behavior." A patient is seated in front of an empty chair; the patient visualizes someone important to them in the chair, someone to whom they have something that needs to be said. While the technique is used to determine why Garrett has kidnapped Mary Beth and where he has hidden her, every character in the novel has an "empty chair" they are forced to confront. For Lucy, it is Davett; she has her moment of justice when she exposes herself to Davett and his wife and daughter. For Garrett, it is his father, who he believes died angry with him. The empty chair for Sachs and Rhyme is most painful of all to confront: it is his, the empty Storm Arrow wheelchair she is forced to confront as she faces the possibility that his surgery will fail and she will lose him. In some ways, their love and need for each other is the most painful baggage Sachs and Rhyme carry.