Clifford Simak

Clifford Donald Simak is a well-known Science Fiction writer. His most famous novels are City, The Goblin Reservation and Way Station; his short story "Huddling Place" appeared in The Science Fiction Hall of Fame, Volume 1.

His works tend to be soft according to Mohs Scale of Sci Fi Hardness, as he's concentrating on characters and story, not on tech, but he doesn't fail physics forever. He tends to be more idealistic than cynical.

What can be said in addition? Let's just say that Isaac Asimov was his Ascended Fanboy.

The author's works provide examples of:

 * Alien Arts Are Appreciated: Way Station. Aliens generally find human food disgusting if not poisonous. Ulysses is an exception; he comes from a species that can live anywhere and eat anything and thinks that Earth coffee is actually the best brew in the Universe.
 * All Myths Are True: The premise of the novel Out of Their Minds.'
 * Alternate Self: The Goblin Reservation
 * Backup Twin
 * Bizarre Alien Biology: Way Station. Any of the Earth animals is much closer to humankind than any alien race.
 * Clarke's Third Law: The Goblin Reservation plays it straight. Magical creatures turn out to have been engineered by Sufficiently Advanced Aliens.
 * Cloning Blues: Duplicates in Good Night, Mr. James are treated as legally and morally expendable.
 * Cosy Catastrophe: The humanity's fate in the City. Human civilization simply lived its course and ended slowly and (relatively) peacefully.
 * Creator Provincialism: Simak often set his stories in Millville, where he was born.
 * Creator Thumbprint: Many.
 * Just One Second Out of Sync, especially if it's used to create alternative Earths.
 * The hero, the love interest, the nonhuman sidekick and a bunch of loonies go on a quest, loonies gradually vanish from the party for reasons directly connected to the reason they went on a journey in the first place, yadda yadda yadda, happy ending, true love, and some mystical higher forces were behind all this.
 * Goblins. He has a very interesting interpretation of goblins as magic eldritch abominations from other dimensions or planets, with reasons unknown, and morality radically different, and their logic will never be understood by us humans.
 * Disability Superpower: The deaf girl from Way Station is pure at heart. Yes, it counts as a superpower.
 * Earth That Used to Be Better: City's main theme is the decline and fall of humanity, so there's plenty of the examples along the way. Eventually the earth reverts to its original state, but its masters are now sentient, industrious and incomprehensible Ants, and what will happen to it is a question.
 * Healing Hands: The deaf girl from Way Station has this as a result of her innocence.
 * Humanity Is Superior: Inverted. Humanity is a young race, if other alien races are adults then humanity is in kindergarten, and going to "school" is one of his favorite plots.
 * Humans Are Special: Way Station and other stories.
 * Kill and Replace: Good Night, Mr. James.
 * This ending was softened when the story was adapted for the original The Outer Limits as "The Duplicate Man":
 * Merging Machine / Tele Frag: Mentioned to have happened in The Goblin Reservation.
 * Monster Clown: Subverted. Ulysses from Way Station looks like one, but he is a very kind person.
 * Necessarily Evil: Humanity in Skirmish. All human development has been based upon synthetic technology of some kind, and thanks to Instant AI, Just Add Water, people must either revert to savagery or knowingly enslave an entire species. (Lamarck Was Right isn't an option here--even a sewing machine comes to life.)
 * No Transhumanism Allowed: Averted for good in City, which eventually brought humanity's downfall. Humans were initially baffled by unexplained disappearances of scientists, transformed to survive the conditions on Jupiter, until one of them finally returned. It happened that the life of the transformed being was so much better, that most population simply left the Earth and their humanity.
 * Our Dragons Are Different: The Goblin Reservation.
 * Our Ghosts Are Different: The Goblin Reservation.
 * Religious Robot: In Message From The Stars, the humans have transcended their physical forms, casting aside their old religions as well as as the robots that used to serve them. Having lost the purpose of serving mankind, the robots have instead turned to Christianity. It is implied that their theological discourse will gradually turn Catholicism into a Robot Religion, just like Afro-American churches tend to have a black Jesus on the cross.
 * Teleporters and Transporters: The Goblin Reservation
 * Time Travel: a number of them, starting from his first short story. Note that in most of his works the timestream can't be changed, a human being can be an observer of the past at most.
 * In City the time travel is impossible -- the time there is a string of Alternate Universes moving through it, so any attempt of time travel will simply bring you to parallel world.
 * Twinmaker: The Goblin Reservation.
 * Our Goblins Are Different: Very different. They are the Fair Folk, for one. And they aren't evil, they are just... well, really alien.
 * Psychic Powers: Time is the Simplest Thing, Ring Around the Sun, the Big Bad in The World of the Red Sun...
 * Also, in his first story, The World of the Red Sun, the main characters place the Time Machine on a plane to avoid being TeleFragged my mountains or buidings.
 * Starfish Aliens: IN SPADES. In The Goblin Reservation we have Wheelers, each of them is a hive of sentient worms in a bag on two wheels using a biological equivalent for rocket engine to move around. Some of aliens, like the Wailer in Special Deliverance, are just incomprehensible. And Way Station seemed to have this as the main idea, as there are only two humanoid species, one of which is a race of natural Genetic Adaptation masters who can live anywhere, so they may be not actually humanoid; another has very bizarre alien biology - they prefer to wear their sould on the outside of their bodies, for one.
 * Ants in the City. They simply ignore everyone else, forcing remaining humans and dogs to leave the Earth for good.
 * Whip It Good: The deaf girl from Way Station is saved from whipping to (implied) death by the main character.
 * Immortality: The main character from Way Station is technically immortal (at least immune to age and sicknesses) while he's inside the station's building.
 * Jenkins, the immortal robot in the City, whose fate is to see the twilight of Humanity.
 * Witch Hunt: Time is the Simplest Thing, witches are people with Psychic Powers. Some of them actually fly on brooms if they want to.