The reverse of the above question deserves a word or two of attention; are there marked cases of delinquency which do not show lying? Surveying the figures of Ferriani[6] who enumerated thousands of lies, belonging to his nine classes of prevarications, which a group of 500 young offenders indulged in, one would think that all delinquents are liars many times over. But as a matter of fact we have been profoundly astonished to discover that a considerable percentage of the cases we have studied, even of repeated offenders, have proved notably truthful. Occasionally the very person who will engage in a major form of delinquency will hesitate to lie. Our experience shows this to be less true, however, of sex delinquency than perhaps of any other. This statement is based on general observations; the accurate correlations have not been worked up. Occasionally the professional criminal of many misdeeds is proud of his uprightness in other spheres of behavior, including veracity. But even here one would have to classify carefully, for it is obvious that the typical swindler would find lying his best cloak of disguise. On the other hand, a bold safe-blower may look down with scorn upon a form of criminality which demands constant mendacity. [6] loc. cit. Realizing that pathological lying is a type of delinquency, and following the rule that for explanation of conduct tendencies one must go to youthful beginnings, we have attempted to gain the fullest possible information about the fundamentals of developmental and family history, early environment, and early mental experiences. Fortunately we have often been able to obtain specific and probably accurate data on heredity. The many cases which have been only partially studied are not included. Successive cross-section studies have been made in a number of cases, and it has been possible to get a varying amount of after-history. Observational, historical, and analytical data thus accumulated have given us a particularly favorable opportunity for discerning the bases of this special delinquent tendency. The results of the various kinds of social treatment which have been undertaken are not the least interesting of our facts. To enumerate the results obtained on the many mental tests given in most cases seems quite unnecessary for the purpose of this monograph. We have referred to a few points of special interest and rarely have designated the results on tests in our series. In general, the reader probably will be better off with merely the statement of the principal findings and of the mental diagnosis.