Probate judges and other trial judges who have heard will contests, and appellate judges and supreme court judges who have reviewed such suits tell us two things: one is that psychiatric testimony or interpretation of the mental status and competency of the testator is more necessary in will contests than is generally recognized; the other is that having a psychiatric witness in court is not an unmixed blessing. To turn to the first of these observations, there are some judges who have come to believe that there should and must be expert neuropsychiatric testimony in all cases where there is lay evidence, needing interpretation, as to the testator's mental incompetence. How this may best be achieved will require a generation of study and experimental application, and will require statutory enactments as well as growth in common law through broad decisions. Its evolution must be toward the expeditious, simple, and economical; the courts and courtrooms are so busy that simplicity and economy of time are veritable essentials. Courts are conducting a business of settling differences practically; practicability has eclipsed the abstract ideal of true and perfect justice in all its ramifications. In essence, the psychiatrist needs much more truth in evidence presented for his interpretation. The experts have both capabilities and limitations. The layman recognizes that not only is the psychiatrist the best informed in the nature of normal and of abnormal human nature, of mental abilities and of mental disabilities, of brain function and of brain disease, but he also recognizes that because the psychiatrist is accustomed to draw reliable conclusions from few data-e.g. spinal fluid cells as counted, unequal pupils and absent knee jerks, different types of memory disorder, inequality of the two sides of the face or of the reflexes of the two sides of the body, or from a confused mind or even a mind in stupor-that if the psychiatrist as expert witness is furnished a sampling of data of the functions of the mind of a deceased testator he is able to