Th e conclusions which emerge from the investigations reported in the rest of the book will be discussed and some of their implications considered in this chapter. With certain reservations the broad statement can be made that the use of objective tests of personality before and after leucotomy enables us to predict the constellation of personality changes following on different types of frontal lobe operations. The pattern of personality changes has been shown to be consistent in the four different types of operation examined, and the alteration in traits may be readily grouped so as to demonstrate changes in the dimensions of personality-viz. a decrease in the strength of traits associated with neuroticism and with intro version and a decrease in certain aspects of intelligence, as shown in the Summary Table.1 The tests also enable us to take count of the differences in the effect of these operations. Altera tions in personality are more pronounced after the posterior Standard operation than the anterior Rostral operation, par ticularly as shown in the table in the sphere of intelligence; and unilateral left operations appear to contribute more than do those on the right to the effect of bilateral Rostral leucotomy.