"Who Speaks of Conquest" by Lan Wright

It's rather a silly novel, setting up a really dumb situation and working that out for most of the book, then trying to rescue some of the stupidity with a little twist right towards the end. By that time, I wasn't buying it! It's one of those ideas that probably would have been OK at about 10,000 words, but that simply doesn't bear the weight of a novel.

The first Terran starship lands at Sirius (why they didn't go to Alpha Centauri first is never explained -- it turns out to be inhabited, so it can't be for lack of planets). There they find a welcoming committee, from an intelligent race that has colonized these planets. They learn that the entire Galaxy is under the rule of the Rihnans, apparently a mostly benign rule, but an unquestioned one. Humans are expected to meekly accept their position. Of course, they don't, and soon an invasion fleet is dispatched from Alpha Centauri. But to the invaders' surprise, the plucky humans decide to fight back, and moreover they have been able to develop some surprisingly good tech, and the humans win.

The Rihnans don't take that lying down, and begin plans for a much bigger fleet to suppress Terra. But the humans have their own ideas, and they decide to take the fight to the rest of the Galaxy before the fight comes to Earth. It turns out that humans are much more ingenious than anyone else (what a surprise!), and so despite lack of numbers it looks like they might win. But the Rihnans do have a special trick up their sleeves.

Luckily the human Captain leading the war effort is able to figure out the Rihnan secret. (Part of which turns out to be telepathy.) He magically becomes telepathic himself, but he is still taken prisoner. And a rescue mission is mounted to the planet he's been taken to, but ... well, why tell the story. The improbable human successes continue, of course, and by the end the Rihnans are swept off their perch. But there is something strange going on ... and as I said some of this implausible human success turns out to have a slightly acceptable explanation. Except it shouldn't have taken 45,000 words of boring easy human successes to get to the twist. And it's not that good of a twist anyway. (Strange at Ectaban)