The study of discrimination and generalization in animals traditionally involves stimuli that are simple, uniform, and restricted in time or space. In recent years, the area of stimulus control has been expanded with the use of stimuli that are complex, extended in time or space, and incorporate or represent natural objects, events, or locations. The contributors to this unique volume have emphasized controlling functions of complex stimulus events — such as location or duration — and their relation to cognitive processes in animals. The chapters cover a wide array of topics, including spatial cognition, categorization, pattern perception, numerosity discriminations, imagery, and spatial tracking, thereby addressing the question of how complex events are perceived, processed, and organized. This volume goes beyond other recent books on animal cognition in that it specifically places some well-known phenomena within the context of stimulus control.