A framework for action planning, called "ideomotor theory," suggests that actions are represented by their perceivable effects. Thus, any activation of the effect image, either endogenously or exogenously, will trigger the corresponding action. We review contemporary studies relating to ideomotor theory in which researchers have investigated various manipulations of action effects and how those effects acquire discriminative control over the actions. Evidence indicates that the knowledge about the relation between response and effect is still a critical component even when other factors, such as stimulus-response or response-response relations, are controlled. When consistent tone effects are provided after responses are made, performance in serial-reaction tasks is better than when the effects are random. Methodology in which acquisition and test stages are used with choice-reaction tasks shows that an action is automatically associated with its effect bilaterally and that anticipation of the effect facilitates action. Ideomotor phenomena include stimulus-response compatibility, in which the perceptual feature of the stimulus activates its corresponding action code when the stimulus itself resembles the effect codes. For this reason, other stimulus-driven action facilitation such as ideomotor action and imitation are treated as ideomotor phenomena and are reviewed. Ideomotor theory also implies that ongoing action affects perception of concurrent events, a topic which we review briefly. Issues concerning ideomotor theory are identified and evaluated. We categorize the range of ideomotor explanations into several groups by whether intermediate steps are assumed to complete sensorimotor transformation or not and by whether a general theoretical framework or a more restricted one is provided by the account. (Contains 7 footnotes, 1 table, and 9 figures.)