This is astrophysicist David Brin's first novel, and it is part hard SF and part mystery (murder and otherwise). A good deal of time is spent introducing a portion of his Uplift setting, explored further in his second (and much awarded) book. I liked it.

The author's background (he was also a NASA consultant) comes through in some fascinating hardware for "diving" towards the surface of the sun and coming safely home again. Outside the basic tech, Brin relies on "galactic tech" to take care of other things, such as artificial gravity.

Of what we learn about the extraterrestrial races, I love the idea of the galactic library. Another clever idea are the magnetovores, grazing the magnetic waves on our sun. And of course the basic idea of uplift is pretty cool, from raunchy dolphins to wisecracking chimpanzees.

First published in 1980, this is the kind of science fiction I read in my youth, though I missed this one at the time. This is also a very quick read. A solid 3½ stars.