Our visual system is constantly exposed to vast amounts of information. A selection process is therefore required to highlight information that is relevant for current actions or bodily needs. Attention to visual stimuli may be guided by two classes of factors: top-down influences based on attentional sets (task relevance, expectations, goals, etc.) and bottom-up saliency (physical characteristics of objects that render them conspicuous within the environment). This thesis used electrophysiological and clinical data to investigate temporal and anatomical correlates of attentional set and saliency on visual selection. Together, our findings show that 1) attentional capture is first influenced by saliency and followed by stimulus relevance, 2) both factors share common anatomical substrates within the dorsal frontoparietal network, and 3) impaired attentional selection in spatial neglect is due to impaired processing of bottom-up (saliency) and top-down attentional set signals.