Chapter 15 begins with an overview of abnormal psychology, addressing the history of views of mental illness and discusses the complicated issue of defining mental illness. In so doing, it introduces the concept of a "family resemblance view" rather than a strict definition. This seems to be a very useful view as it works well with the fact that mental disorders may have several similar features rather than any defining characteristic common to all of them. From there it summarizes specific mental disorders such as anxiety disorders, schizophrenia, mood disorders, and culturally specific disorders.
In its discussion of defining a concept of mental illness, the book touches on many misconceptions held by the general public. As a subject which is difficult to define and classify for experts, it makes sense that the rest of the population would hold many erroneous beliefs about mental illness; however, many of these seem to stem from much simpler misconceptions such as those discussed at the beginning of the textbook. People may see pop psychology labels or "dueling expert witnesses" and conclude that diagnoses are meaningless. Some also deny the existence of mental illness entirely perhaps because of a belief that the mind exists in a magical realm entirely outside the brain similar to historical beliefs about the spiritual nature of mental illness.