The Haunted Stars by Edmond Hamilton (1960)
Edmond Hamilton had a long career as a science fiction writer; his first story was published in 1926, just two years before his good friend Jack Williamson made his professional debut. Like Williamson, Hamilton was known for years for his exotic, slam-bang, galaxy-stretching, pulp tales. (In fact, Hamilton was known in SF circles as "World Wrecker" Hamilton. And, like Williamson, over the years he proved that he could also write thought-provoking, mature science fiction. The Hamilton who wrote The Haunted Stars is a far cry from the Hamilton who gave us the juvenile Captain Future saga.
The time is 1965. The United States and Russia are still in a battle for political supremacy. Shocked by Russia's launching of the Sputnik, the US rapidly develops a space program and when the book opens both the US and Russia have managed to establish footing on the moon. The US base -- a secretive installation that allows no outside visiters -- is in the Gassendi Crater. Russia is pushing the UN to force America to open the base for inspection, as the Russians have done with their two moon bases.
Robert Fairlie is a professor of linguistics and a noted philological researcher. He is called (he thinks) to the Smithsonian for some unknown urgent project. Once at the Smithsonian, he is whisked away to Morrow Base, New Mexico -- the center of the US space effort. Fairlie discovers that he is not the only person mysteriously summoned; three other world-reknown philogolists have also been gathered. They learn the government's big secret -- we are not alone.
Americans have discovered that the Gassendi crater was once held a large community of aliens who were destroyed by an atomic attack 30,000 years ago. The remants of the aliens are scant. No machines, No hint of who they were nor what their advanced technology was. There were some writings found and a strange ball that turned out to be a recording device of a woman singing in an alien language, Fairlie and his colleagues are tasked with decoding the mysterious language, an impossible task.
How Fairlie was able to begin to translate the language is only the beginning. Then comes the effort to find and communicate with the race that had built the ancient moon base. What will he find? An ancient race that appears to have been friendly to our ancestors, or the other race, the race that destroyed and obliberated almost any trace of the millennia-old moon base and its people?
A fast-moving, well-written SF adventure with a convincing cast of characters.