Experience of neurotic patients seeking treatment convinces me that paranoia is by no means so rare a disease as asylum statistics would lead one to suppose. For the purposes of the latter, of course, only fully developed and alienated cases are taken into account. Of the four cases to be discussed here, only one has said or done anything that could be recorded in a certificate, and the delusional picture was only unfolded at the patient's goodwill. None of these cases therefore would figure in statistics, yet all four are drawn in a short space of time from a limited section of the community. Paranoid trends, episodes or systems are, I believe, quite common in intelligent, cultured and well-developed minds, and account for a substantial amount of insufficiency and unhappiness. Apart, therefore, from the question of the treatment of the delusional asylum patient, the projected mental clinics will find themselves faced with a formidable problem in regard to the treatment of paranoid conditions. It is from the incipient and partial cases of paranoia that we can gain an insight into the factors which arrest or promote the disease. Only in the most exceptional cases does the fully developed paranoiac admit us within the circle of his fortifications.