Le Guin says in her introduction that "The Rock That Changed Things" and "Newton's Sleep" were the stories that she had the most grief with, and in my opinion they are clearly the least successful in the volume. The first is a parable about different ways of perceiving the world and about the relationship between men and women (or perhaps between the owners and the dispossessed). For me, at least, it fell flat on its face — it is too unsubtle and too close to its target to make a good parable. (I also thought that the repeated use of the word "rape" in situations otherwise unmarked for discomfort, let alone pain and degradation, was insensitive — and somewhat odd, coming from a "born-again" feminist like Le Guin.) In "Newton's Sleep" the protagonist, Ike, is one of a group who have built a space station to escape from an Earth torn by plague and ecological disasters. He is firmly convinced of his own rationality and the virtues of reason, but his world falls apart completely when the space station is infested by ghosts. The setting and the characters of Ike and his family are developed nicely, but the conclusion doesn't work at all: resorting to the supernatural in order to demonstrate that people are essentially irrational is both unnecessary and ineffective. (No doubt the external events are supposed to mirror the internal ones, as in A Wizard of Earthsea, but I don't buy it here.)
The three short pieces (six to ten pages each) can't really be described: "The Ascent of the North Face" is a completely frivolous joke; "The First Contact with the Gorgonids" is a perfectly ordinary "aliens land and encounter humans" story, but one which has an edge despite its humour; and "The Kerastion" is a short but powerful evocation of an imaginary culture through participant-description of an unusual ritual.
The last three stories in the collection are set in the universe of the Ekumen (the setting of much of Le Guin's earlier science fiction) and involve that golden oldie of science fiction — faster-than-light travel. "The Shobies' Story" is about the first humans to use the ftl drive. As usual, things don't go quite as expected, previous experiments with mice notwithstanding... In "Dancing to Ganam" the ftl drive is just a device, and the story is about an anthropologist who completely misunderstands the culture he is investigating. The eponymous "A Fisherman of the Inland Sea" is the longest story in the collection and, in my opinion, the most outstanding. It uses the time-dilation effects of relativistic travel (not to mention time-travel!) to highlight the emotional development of its protagonist, who, like Shevek in The Dispossessed, is himself a physicist. Also of interest is the unusual marriage system on his home planet.
A Fisherman of the Inland Sea is a great collection, and one that won't disappoint Le Guin's fans (even those who may have been put off by some of her more recent work.)