A Deepness in the Sky, by Vernor Vinge

In Book 2 of his Zones of Thought series, Vernor Vinge rolls back the clock thousands of years before the events of A Fire Upon the Deep to an earlier time in human's reach around the galaxy.  A mysterious star, appropriately called OnOff, goes through periods of decades of brightness and decades of darkness.  The sentient spider-like species who lives on a planet in that system are on the verge of a technological revolution, roughly parallel to the late twentieth century on Earth.

Meanwhile, two groups of humans, the Qeng Ho and the Emergents, meet up on a mission to investigate OnOff.  Their competing visions lead to a devastating battle.  They need supplies to return back to open space, but the spider world doesn't have the technological capacity to provide supplies.  So they wait.  And wait.  For decades.  The humans develop a new cultural symbiosis of victor and victim, while the spiders develop their technology.

A Deepness in the Sky is long and slow to develop, but I must say that Vinge doesn't waste a lot of plot.  The story elements work together and drive forward to a satisfying, expansive conclusion.  For the patient reader, the payoff of the story is solid.  Epic in scope and decades in the telling, A Deepness in the Sky is worthy of the awards it was given.