"On September 15, 1906, the Training School for Backward and Feeble-minded Children at Vineland, New Jersey, opened a laboratory and a Department of Research for the study of feeble-mindedness. A beginning was made in studying the mental condition of the children who lived in the Institution, with a view to determining the mental and physical peculiarities of the different grades and types, to getting an accurate record of what deficiencies each child had and what he was capable of doing, with the hope that in time these records could be correlated with the condition of the nervous system of the child, if he should die while in the Institution and an autopsy should be allowed. As soon as possible after the beginning of this work, a definite start was made toward determining the cause of feeble-mindedness. After some preliminary work, it was concluded that the only way to get the information needed was by sending trained workers to the homes of the children, to learn by careful and wise questioning the facts that could be obtained. It was a great surprise to us to discover so much mental defect in the families of so many of these children. The results of the study of more than 300 families will soon be published, showing that about 65 per cent of these children have the hereditary taint. The present study of the Kallikak family is a genuine story of real people. The name is, of course, fictitious, as are all of the names throughout the story. The results here presented come after two years of constant work, investigating the conditions of this family. To the scientific reader we would say that the data here presented are, we believe, accurate to a high degree. It is true that we have made rather dogmatic statements and have drawn conclusions that do not seem scientifically warranted from the data. We have done this because it seems necessary to make these statements and conclusions for the benefit of the lay reader, and it was impossible to present in this book all of the data that would substantiate them. We have, as a matter of fact, drawn upon the material which is soon to be presented in a larger book. The reference to Mendelism is an illustration of what we mean"--Preface. (PsycINFO Database Record (c) 2005 APA, all rights reserved).