The best I've read in a long time is the Void Trilogy from Stephen Baxter
It's full speed from start to finish. Amazing storytelling.
AD 3580. The Commonwealth has spread its civilization throughout the galaxy. Its citizens are privileged and protected by a powerful navy. And at the galaxy’s centre is the Void, a sealed universe created by aliens billions of years ago. Yet the Void isn’t inert. It’s expanding – and now it wants to make contact.
The Void chooses Inigo as its conduit and he channels dreams of a simpler, better life within its bounds. His visions attract followers – determined to seek this utopia. And they’ll cross the Void’s forbidden boundaries to reach it. However, this act could trigger push it to grow beyond all control . . . destroying everything in its path.
All Stephan Baxter Commonwealth series are epic.
It's from 2007-2010 though.