The only extant, medieval manuscript names the author as "Scylax"' (or "Skylax"), but scholars have proven that this attribution is to be treated as a so-called "pseudepigraphical appeal to authority": Herodotus mentions a Scylax of Caryanda, a Greek navigator who in the late sixth century BC explored the coast of the Indian Ocean on behalf of the Persians.
[1] Many details in the work, however, reflect fourth-century BC knowledge of the world; since it cannot be by the sixth-century Scylax, its author is habitually referred to as Pseudo-Scylax.
The narrative attributed to this "Pseudo-Scylax" simulates a clockwise circumnavigation of the Mediterranean and Black Sea, starting in Iberia and ending in West Africa, beyond the Pillars of Hercules, that mark the Straits of Gibraltar.
The NW African section is sometimes claimed to have been derived from the earlier Periplus of Hanno the Navigator, but a close comparison makes the differences between the two texts apparent.
The Periplus of Scylax, along with other minor ancient Greek geographers, was first published in Augsburg in 1600 by David Hoeschel.