THE TERRAN PRIVATEER is the first novel of the DUCHY OF TERRA series by Glynn Stewart. I am already familiar with Glynn Stewart due to the fantastic STARSHIP'S MAGE series. That series was about magicians able to move starships through hyperspace. This is a more grounded series about the idea of Earth making First Contact with an expansionist alien race, only to be swiftly conquered. Which is quite the hook.