The medical history and treatment of a very young patient, which we present in this book, does not originate, to be precise, from my own records. Of course, I had overall supervision of the therapeutic program and I only spoke with the child myself on one single occasion.

The therapeutic regimen itself was carried out by the child's father, to whom I owe genuine gratitude for providing me with his notes to publish. However, the father's contribution does not stop there.

I believe that no other person would have managed to convince the child to confess so much. (. . .) The coincidence of tender interest with scientific interest in the same person allowed for the method to be applied in this case in a way that would be inappropriate in another case. (. . .)

[Excerpt from the text of the introduction of the edition]