Frederik Pohl

When the first message from space arrived on Earth, five people who were on their way to the eschaton were busy at their own affairs. For one, Dr. Pat Adcock was having a really bad day with her accountant in New York. For another, Commander (or, actually, by then already ex-Commander) Jimmy Peng-tsu Lin was on the lanai of his mother's estate on Maui, glumly running up his mother's telephone bill with fruitless begging calls to every influential person he knew. Major General Martín Delasquez had just been given his second star by the high governor of the sovereign state of Florida. Doctorat-nauk (emeritus) Rosaleen Artzybachova was discontentedly trying to make the time pass with chess-by-fax games against a variety of opponents from her boring retirement dacha outside of Kiev. And Dan Dannerman was holed up in a seedy pension in Linz, Province of Austria. He was hiding from the Bundes Kriminalamt with a woman named Ilse, who has by profession an enforcer for the terrorist Free Bavaria Bund, more commonly referred to as the Mad King Ludwigs. (Dannerman himself was a mere courier in the same group.) Most of these five people had not even met each other yet. Pat Adcock, being an astronomer by profession, might conceivably have had some rough idea of how the message would affect all their lives, though even she couldn't have known just how, or how very much. None of the others could have had a clue.

From the Booklist review by Dennis Winters: 

With aliens on the way to Earth, an oddly assorted group gathers at a New York observatory. Against the backdrop of a grim and finely detailed near-future world, a secret agent, the observatory director (his cousin), a Chinese astronaut, a retired professor, and a general from the (almost) sovereign State of Florida become involved in international intrigue, personal conflicts, and the long-awaited first contact with aliens who may be the direst enemies of humanity. Held in captivity by the aliens (who seem both friend and foe to Earth), the humans must maintain their sanity and their purpose under puzzling and repugnant conditions, including their captors' ability to construct duplicates of them. The aliens' involvement, along with their human prisoners, in an appalling interstellar war brings the story to an unresolved climax; more is to come. Pohl's sf mastery is again evident, as his deceptively simple style carries the action easily and hypnotically to a nonconclusion that has us gasping for more. 

From Kirkus Reviews:

In the near future, two brief strange messages from space aliens arrive on Earth, while in a US racked by pollution, crime, nuclear terrorism, and hyperinflation, Dr. Pat Adcock suspects that aliens have landed on her abandoned orbiting Starlab. To go and investigate, she puts together a team that includes herself, pilots Jimmy Lin and Martín Delasquez, old astronomer Rosaleen Artzybachova, and bodyguard Dan Dannerman (secretly a spook, he's also Pat's cousin). Starlab, they discover, is infested with weird alien devices, and then, abruptly, they find themselves thousands of light-years away, prisoners of alien ``Dopeys'' and ``Docs'' who are experimenting on them! According to the aliens, their Beloved Leaders need Earth's help against outlaw terrorist Horch. Seems that the two sets of aliens are fighting over who controls the ``eschaton,'' a time in the remote future when everyone who ever lived will rise again and live forever! Pat, Dan, and company learn that they are copies, their originals having been sent back to Earth with altered memories; still other copies have been subjected to horrible vivisection experiments. And the Horch add to the confusion by claiming that the Beloved Leaders are actually ruthless, planet-destroying tyrants. An impeccably crafted, absorbing, and enjoyable reworking of mostly familiar material that, while satisfyingly self-contained, seems perfectly poised for sequels.
-Copyright ©1996, Kirkus Associates, LP. All rights reserved.

"The story is conceived and executed with Pohl's usual acumen."