V isual short-term memory has a very limited storage capacity of about three objects. Some stages of categorization and decision making appear also to have very sharp capacity limitations, sometimes as low as one representation. Early visual processing, on the other hand, is massively parallel and can deliver many more stimuli for further processing than can be stored or acted upon. In this chapter, we review recent work from our laboratories that explores how early and late attentional mechanisms interact to select and store information of interest to the observer. The studies are based on the analysis of electrophysiological and magnetoencephalographic recordings using paradigms that allowed us to track the moment-to-moment deployment of visual spatial attention and the participation of visual short-term memory in ongoing cognitive processing.