The Ophiuchi Hotline (1977) by John Varley
"There are many aliens out there in the depths of space.
Out somewhere in that vast dark, the Ophiuchi Hotline has been broadcasting the entire sum of an alien race's knowledge. Little has been decrypted but that which has is of fabulous value.
Back here in the Solar System, but not on Earth, there are the half-human hybrids, divorced from the rest of humanity's concerns, freed from the gravity wells of planets, living their lives as artists of outer space.
Not all aliens are friendly however: Other aliens came, devastated our civilisation and threw Earth-based humanity back into the stone age. Then they took up residence on Jupiter, maintaining a quiet but forbidding presence.
Knowledge gleaned from the Ophiuchi Hotline allowed the Lunar and other colonies to survive. Life goes on and most people accept the new state of affairs. They believe that there is nothing they can do to reclaim Earth or to expel the aliens from Jupiter.
Tweed is not one of these people. He's the ex-President and a master criminal. He is determined to use any means possible, within or outside the law, to regain what he believes is humanity's birthright: the Solar System and everything within it.
Lilo is a scientist and another criminal. She has been found guilty of the capital crime of illegal biological research. Although she's going to die, she plans that her clone, secreted far from Earth and due to awaken soon, will take over her life's work.
Tweed, however, wants Lilo and her knowledge. He won't let a mere death sentence get in his way. He's after her and her clone.
Now there's a new problem. After four hundred years, the latest decryptions from the Ophiuchi Hotline appear to be saying that the information is not a free gift. Now it seems that the alien masters of the Ophiuchi Hotline are demanding payment and no-one knows what payment, or when, or what dread penalties will entail if the debt remains unpaid.
Fabulous, wonderful stuff. This is John Varley's first novel, and he was rightly called "The New Heinlein". It stunned me when I first read, it remains a favorite and I became a firm fan of his writing. It's got intriguing characters: the humans Lilo, Cathay, Vaffa and Mari. And then of course the wonderful Parameter-Solstice, free from the constraints of space-suits and spaceships, just floating in space.
What's it got: a beautiful babe as a heroine, in fact several of them all over the Solar System; an evil criminal genius, inscrutable aliens, more aliens, and alien-human symbiotes cloning all over the place, romance and excitement."
- SF Reviews
This book was by no means up to the standards I had expected from reading his Titan trilogy. I can see the parallels with Heinlein and I just don't really like that style of writing. If I was to recommend a John Varley book then this would not be it.