Star Wars: Thrawn Ascendancy (Book I: Chaos Rising)

Beyond the edge of the galaxy lies the Unknown Regions: chaotic, uncharted, and near impassable, with hidden secrets and dangers in equal measure. And nestled within its swirling chaos is the Ascendancy, home to the enigmatic Chiss and the nine ruling families that lead them. The peace of the Ascendancy, a beacon of calm and stability, is shattered after a daring attack on the Chiss capital that leaves no trace of the enemy. Baffled, the Ascendancy dispatches Thrawn, one of its brightest young military officers, to root out the unseen assailants.