The Engines of God by Jack McDevitt It's early in the 23rd century, the age of space technology. Hutch is the pilot sent to evacuate a group of archeologists off of a world with a dead civilization, set to be terraformed. While she is there, she learns a lot about alien archeology, including some patterns of civilizations' decay. Her interest in alien archeology leads her on a dangerous adventure, uncovering knowledge that threatens her own civilization.
The world portrayed here is highly unlikely for a futuristic world, portraying the world much as it is now, with the largest difference being an incredible advance in space technology. In the acknowledgements, McDevitt says that Christian Epoch dates are used out of respect for everyone's sanity, but a whole lot more that dates from the current time are used. McDevitt assumes that societal values would stay constant, his constant being out of date already. Early in the book, we are told that marriages in this system expire in 5 years, a system which is not used later in the book, and which I cannot imagine being put into use. The actual threat to civilization is an interesting idea, but it is anticlimatical by the time it is presented, at the very end of the book.
Happy reading.