Salamis is the fifth novel in Harry Turtledove's critically acclaimed Hellenic Traders series. Creating an intricately detailed world (as Turtledove is famous for doing), the series details the adventures of two cousins, Menedemos and Sostratos who work as seaborne traders following the death of Alexander the Great.
In 306 BC, the small, free, and independent polis of Rhodes is trying to stay neutral between the local great powers, each ruled by one of Alexander the Great's marshals: Asia Minor, controlled by one-eyed Antigonos, and the Egypt of Ptolemaios. Antigonos' son, Demetrios, comes to Rhodes seeking an alliance against Ptolemaios. The Rhodians, who trade a lot with Egypt, refuse his offer.
Menedemos and Sostratos take the Aphrodite to Egypt for business...and to tell Ptolemaios what has been going on. Just before they leave, they learn Demetrios has invaded the island of Cyprus, which Ptolemaios dominates. He is advancing on the southeastern town of Salamis, where Ptolemaios' brother, Menelaos, has concentrated his forces.
After they pass on their news, Menedemos does business in the brash new city of Alexandria while Sostratos travels up the Nile to old, old Memphis to trade there, and to see the Pyramids and the Sphinx. Ptolemaios, meanwhile, readies a fleet to rescue his brother and drive Demetrios back to Asia Minor.
Ptolemaios, needing shipping to carry weapons for the army he intends to land, coerces Menedemos into bringing the Aphrodite along as part of his expeditionary force. And so, very much against their will, Menedemos and Sostratos become small parts of one of the ancient world's greatest naval battles.