The many forms of suicidal phenomena, including contemplated, attempted, and completed suicide, present significant problems to both researchers and practitioners. Although many attempts have been made to develop categories, agreement among the proposed systems has been more the exception than the rule. This article reviews theoretical and empirical efforts to define types of suicidal individuals and attempts to integrate them by means of higher-order categories of variables. These categories or "dimensions" are as follows: (1) descriptive, (2) situational, (3) psychological/behavioral, and (4) teleological. Implications for research and practice are discussed.