Observations of the spontaneous play of nurseryschool children by the one-minute sampling method showed: that leadership may be consistently recorded by this method; that 60 one-minute samples of behavior furnish reliable measures of leadership when appropriate weights are assigned to the various categories of leadership; and that even at the preschool age there are two definite types of leaders, the "diplomat" and the "bully." The former, by indirect suggestions, controls a large number of children; the latter employs brute force in "bossing" the small group he has chosen for his "gang." Independent play is most characteristic of all ages, but decreases in frequency as the children grow older. Sex differences in leadership are negligible. Leaders somewhat exceed non-leaders in intelligence. There was a trend toward development of leadership as the school year advanced. (PsycINFO Database Record (c) 2006 APA, all rights reserved)