Cobra: Timothy Zahn

Book I of Cobra. The colony worlds of Adirondack and Silvern fell to the Troft forces almost without a struggle. Outnumbered and on the defensive, Earth made a desperate decision - it would attack the aliens not from space, but on the ground - with forces the Trofts would never suspect...And so the cobras were created - a guerilla force whose weapons were surgically implanted, invisible to the unsuspecting eye yet undeniably deadly. But power brings temptation - not all the Cobras could be trusted to fight for Earth alone...Cover art by Eddie Jones.