As I mentioned in my write-up of Skirmish (a collection of short stories by Simak), one of the things I really appreciate about Simak is he explores some of the consequences of the hypothetical condition posed.
For example, in this novel, an organization, called Fishhook, has developed the resources to telepathically travel to other planets. They interact/learn from aliens and become a mega-monopoly on providing the technologies, philosophies, etc from aliens to humans on earth. Simak notes that teleportation technology will completely wipe out entire industries: the trucking/shipping industry, gas stations, tire manufacturers, etc. Furthermore, science fiction frequently focuses on immensely talented/intelligent protagonists, without getting into the psychology of the rest of the people. Simak covers this aspect a bit better in the novel, exploring the situation where the development of mental powers like telepathy and levitation, gets severely misinterpreted by the masses and beliefs in the supernatural: hexes, witches, warewolves and the like makes a major comeback.
That being said, there's a few major issues I took with this novel.
- Simak tells a story that is just too conveniently knit-together. Characters, who in a more realistic story would probably one-off mentions or meetings, end up becoming major characters / plot-points.
- Simak has a similar theme to X-Men super-human persecution issue, which is rather clumsily done. The protoganist' adoption of this cause seems rather sudden as well.
- Female characters are cartoonish. The two female characters are of course attrractive. And one becomes unrealistically instantly attracted to the protoganist.