The main purpose of this chapter is to address the field of architecture in a way that makes it more comfortable with psychoanalysis and its methods of diagnosis. Let me start off by saying that putting architecture together with psychoanalysis is different from putting it together with philosophy. On one hand, psychoanalysis isn’t philosophy because it is a science. It was founded largely by neurologists and always keeps a close alliance to the field of medicine. And yet, because of this link to medicine, clinical psychoanalysis also carries a Hippocratic ethic that is not mandatory to philosophy. Psychoanalysis as a practice involves observation, diagnosis and treatment, and it is diagnosis that stands today as one of the more urgent and important interdisciplinary methodological hurdles between architecture and psychoanalysis. The benefits of jumping this hurdle are substantial and so my objective is to introduce the method by setting out some definitions and examples, and along the way, to remind ourselves of how psychoanalytic diagnosis is already being used in the field of architecture.