To provide an overview of the history, evolution, and nosology of the diagnostic constructs for "borderline syndrome of childhood," also known as "multiple complex developmental disorder." The authors synthesized information found via electronic searches of databases (MEDLINE, PsycINFO, Current Contents, Humanities Abstracts, and Social Sciences Abstracts) and bibliographic directed searches. Although early publications (prior to 1980) were either highly anecdotal or lacking in scientific rigor, they were nonetheless noted for their historic value and influence on research trends. The recent publications (1990s) were characterized by more rigorous methodology and greater generalizability. Current classifications, proposals for diagnostic criteria, epidemiological data, and nosological suggestions were summarized. The literature supports the creation of a new diagnostic label to describe a population of children whose symptoms are currently subsumed under the labels "borderline" or "multiple complex developmental disorder." A full characterization of the syndrome, including its evolution, would require prospective studies and may differ from the known evolution for personality disorders and/or pervasive developmental disorders. The authors propose a process by which a new nomenclature is derived.