THIS IS A report of a follow-up investigation conducted during the first six months of 1969. The subjects are patients who were extensively studied in a systematic research program on the "borderline syndrome," carried out between 1961 and 1968 at the Psychosomatic and Psychiatric Institute (P&PI) of Michael Reese Hospital and Medical Center. The original research is published in the book by Grinker et al1 titled the Borderline Syndrome. In this book we reported on four investigations: 1. Observations of the behavior of a sample of patients, hospitalized on the Michael Reese floor of the Illinois State Psychiatric Institute (ISPI), were made. The behavioral observations when clinically assessed in an ego functions framework became the basic data used to define the "borderline syndrome" and its four subcategories. 2. Individual case studies of borderline patients hospitalized at P&PI were developed to illustrate vividly the characteristics of the subcategories of the