In the early 1960s, the head of a prominent New York City Child Development Center and a psychiatrist from Columbia University launched a study designed to track the development of twins and triplets given up for adoption and raised by different families. The controversial and disturbing catch? None of the adoptive parents had been told that they were raising a twin - the study's investigators insisted that the separation be kept secret. Here, Nancy Segal reveals the inside stories of the agency that separated the twins, and the collaborating psychiatrists who, along with their cadre of colleagues, observed the twins until they turned 12.

Interviews with colleagues, friends, and family members of the agency's psychiatric consultant and the study's principal investigator, as well as a former agency administrator, research assistants, journalists, ethicists, attorneys, and - most importantly - the twins and their families who were unwitting participants in this controversial study, are riveting. Through records, letters, and other documents, Segal further discloses the investigators' attempts to engage other agencies in separating twins, their efforts to avoid media exposure, their worries over informed consent issues in the 1970s, and the steps taken toward avoiding lawsuits while hoping to enjoy the fruits of publication.