Você poderia estar pensando na trilogia Conquistadores de Timothy Zahn?
Data de 1994; o primeiro livro lida com uma raça de alienígenas atacando um império humano; enquanto o segundo livro é principalmente contado a partir da perspectiva dos alienígenas.
Se isso servir para manter sua memória ainda mais ativa, os alienígenas têm naves que parecem ser quase indestrutíveis e têm comunicações muito mais rápidas graças aos seus Anciões.
Há um resumo muito melhor do primeiro romance na Amazon:
Timothy Zahn, Hugo Award-winning author of The New York Times best-selling Star Wars trilogy, blazes a spectacular new path across the sky in an epic original novel of star-spanning action adventure, mystery and intrigue. A long era of peace and prosperity in the interstellar Commonwealth has suddenly come to an end. Four alien starships of unknown origin have attacked, without provocation, an eight-ship Peacemaker task force, utterly destroying it in six savage minutes. The authorities claim there were no survivors. But Lord Stewart Cavanaugh, a former member of Parliament, has learned through back channels that one man may have survived to be captured by the aliens: his son, Commander Pheylan Cavanaugh. A large-scale invasion appears imminent, and the strictest security measures are in effect . . . measures that Lord Cavanaugh has no choice but to defy. He recruits Adam Quinn, who once flew with the elite Copperheads--fighter pilots whose minds are literally one with their machines--to rescue his son. Quinn assembles a crack force of Copperheads to steal out of the Commonwealth security zone and snatch Pheylan Cavanaugh from the conquerors. Depending on the outcome, Quinn and his men will retum home as heroes or as the galaxy's most despised traitors--if they come home at all.