Private behavioral events are those events in which the stimulation with respect to which an individual responds is not accessible from the vantage point of another person. In such cases, the stimulation may be verbal or nonverbal. Further, the responses with respect to this stimulation may be verbal or nonverbal, and accessible or not to others. One type of private event involves verbal reports occasioned by conditions of the body, such as aches and pains. A second type involves covert operant behavior, such as thinking, problem solving, and daydreaming. For each type, a naturalistic account may be developed based on concepts derived from the analysis of overt behavior. Key words: B. F. Skinner, private behavioral events, problem of privacy, problem solving, thinking, verbal reports.