The superior longitudinal fasciculus and the arcuate fasciculus have long been considered synonymous in the human, and these names have been used interchangeably. According to observations in the monkey, however, they are separate entities. The SLF comprises three subcomponents linking the parietal lobe association cortices with the frontal lobe. The AF, by contrast, appears to be separate and distinct from the SLF. This chapter presents a historical account of SLF and AF. It reviews the origins of the earlier notions and (...) how the understanding of these fiber bundles became embedded in neurological anatomy and perpetuated in current terminology. (shrink)