Zelazny is sneaky. He doesn't tell you straight off what's going on in this novel. You have to discover what's happening the same way the characters do... step by step as events take place.
This Immortal was a Winner of the HUGO AWARD for Science Fiction. Roger Zelazny has also penned the well-known Chronicles of Amber, Lord Demon, Night in the Lonesome October, The Dream Master, To Die in Italbar, Route 666, and other SF and some mystery novels.
FROM BACK COVER: The life history of Conrad Nimikos was an enigma that faded out in lost records and obscurity a few decades back. Some said he had once had a different name, that of the man who had fought the Vegan empire to a standoff. Some even said that he had other names, stretching back through the centuries...
But this was not time to talk about the past; the future was at stake. For the Vegans were returning on a mission of conquest--and soon the place of Earth among the stars would be decided.
This is the long version of "And Call Me Conrad" that appeared in The Magazine of Fantasy and Science
It shared the Hugo with Dune the year it came out. While it was an entertaining book (I think it was Zelazny's first novel), it is NOT as good as Dune. Sorry.