I first encountered Sundiver years ago, and I recall that when I first read it I didn't think much of it. I almost didn't more on to the other novels in the Uplift saga because of this, but on a friend's recommendation I did, and I'm glad of it. I hadn't read Sundiver in years, preferring to reread the other Uplift novels instead. Recently, though, I decided to give the first novel another chance -- and I'm glad I did that, too. I don't know if it's the benefit of hindsight or simply seeing Sundiver in the context of the other Uplift novels or both, but it turns out that Sundiver was better the second time around.

Sundiver's pages are spent in the company of Jacob Demwa, a special operative working in a more-or-less unofficial capacity for the Terragens Council. We first encounter him working with a newly uplifted dolphin (uplift being the process of genetically enhancing a near-sentient species to full sentience) -- but he is called away from this job to join the Sundiver project, a Mercury-based expedition to explore the sun -- and it turns out life has been discovered there. What follows are a series of mysteries, interspersed with author David Brin's vivid evocations of what it might be like to actually be inside a stellar atmosphere. Brin does a very good job all around -- his training as a physicist serves him well from a "hard science" viewpoint. His description of the sundiver ship is both poetic and believable, and he also does a great job with the mysteries Demwa must solve, which include a murder, what the solar lifeforms may (or may not) be, why the "shepherds" of these life forms are so hostile towards the sundivers and what the motivations of the various human and alien characters are.

Speaking of which, Brin does a great job with character in this novel. Demwa, being the focus of the narrative, is the best-defined of them all, but others -- Dr. Shriver, for instance, and Kanten Fagin -- are well-written and believable. But it is Demwa who is the heart of Sundiver, and I wish Brin would do something more with him, another novel or a short story or something! Demwa is equal parts special operative, private investigator, criminal and psychological case history -- recovering from the death of his wife, he has hypnotized himself into a split personality -- the "normal" Demwa and "Mr. Hyde," who contains all of Jake's antisocial tendencies, and who takes over from time to time in unpredictable and unsettling ways. Demwa is unusual and engaging, and it is largely because of him that Sundiver is such a great read.

Of course, Sundiver is the first part of Brin's ongoing Uplift series, and as such does a lot of establishing -- introducing aliens like the Kanten, and the Pila, and mentioning aliens that will grow to play major roles in later Uplift novels, like the Soro and the prankish Tymbrimi. Brin also introduces the Uplift concept here, and the essential dichotomy of the Uplift universe: Every sentient species in the Five Galaxies has been uplifted by a patron species -- or so it is believed until mankind comes along. Humanity is a so-called "wolfling" race, a race with no known patrons ... or if those patrons do exist, they abandoned humanity millenna ago, and will not admit to the crime of client abandonment. Humans might have been adopted as someone else's clients -- but for the fact that they have uplifted clients of their own, chimpanzees and dolphins, with talk of dogs soon to follow (an intriguing thread Brin unfortunately never returns to). This automatically gives them the status of a patron race -- which angers the Soro, the Pila and others no end. Much of the outcome of Sundiver, as well as the other Uplift novels, hinges on whether or not men will keep their patron status, or whether the Galactics' political maneuvering will reduce them to client status.

A crowded universe is Brin's great concept here -- a univese literally stuffed end-to-end with species that have existed for thousands of centuries ... and in which humans may have no place, where our very existence as free people is in jeapoardy. Brin returns to this "free existence" theme in other guises in many of his novels, such as The Postman and Glory Season, but nowhere is it as crisp and as immediate as it is in Sundiver. It serves as a great introduction to the Uplift saga (currently at six books; it's unclear whether Brin will write more); but it also works very well indeed as a stand-alone novel of mystery and science, of one man and his mental health, and of humanity's place in the cosmos.