We are concerned with individuals who live in freedom, some of them suffering intensely from their abnormal organization, but otherwise ordinary members of society.

In a few cases we are concerned with individuals whose moral or artistic ideals have widely influenced their fellows, who know nothing of the peculiar organization which has largely molded those ideals.
I am indebted to several friends for notes, observations, and correspondence on this subject, more especially to one, referred to as "Z.," and to another as "Q.," who have obtained a considerable number of reliable histories for me, and have also supplied many valuable notes; to "Josiah Flynt" (whose articles on tramps in _Atlantic Monthly_ and _Harper's Magazine_ have attracted wide attention) for an appendix on homosexuality among tramps; to Drs.

Kiernan, Lydston, and Talbot for assistance at various points noted in the text; and to Dr.K., an American woman physician, who kindly assisted me in obtaining cases, and has also supplied an appendix.

Other obligations are mentioned in the text.
All those portions of the book which are of medical or medico-legal interest, including most of the cases, have appeared during the last three years in the _Alienist and Neurologist_, the _Journal of Mental Science_, the _Centralblatt fuer Nervenheilkunde_, the _Medico-legal Journal_, and the _Archivo delle Psicopatie Sessuale_.

The cases, as they appear in the present volume, have been slightly condensed, but nothing of genuine psychological interest has been omitted.