"Dark Visions" (2000) is a new edition of a 1988 anthology called "Night Visions 5: The Skin Trade."
It includes 3 short stories by Stephen King, 3 more by Dan Simmons, and one by George R.R. Martin.
King's contributions are "Reploids", "Sneakers", and "Dedication." Reploids is very short and goes nowhere. "Sneakers" is okay. Some parts are pretty cool. It's basically about a haunted men's room. (I kid you not.) "Dedication" is pretty gross. (As part of a black magic spell, a woman eats a man's congealing semen off of his sheets.) It gets points for the originality of its disgusting premise, but it's not a great story. Plus, if I'm not mistaken, all three stories are reprinted in King's collection "Nightmares & Dreamscapes."
Dan Simmons' contributions are "Metastasis" -- which is great -- "Vanni Fucci is Alive and Well and Living in Hell", and "Iverson's Pits." Metastasis is about supernatural slug-like creatures that cause cancer. They're usually invisible. Only one man is able to see them, and he invents a technique for drawing them out of their victims. "Vanni Fucci" is about a damned man and is slightly comedic. It's an okay story. A lot of Dan Simmons' fans think "Iverson's Pits" is the best of the three, but I liked it least. It's about Civil War ghosts, I think. (It's been a while since I read it.) Like Stephen King's stories, these three Dan Simmons stories were reprinted elsewhere. I think they're in the collection "Prayers to Broken Stones."
The best story is the last and also the longest. It's George R.R. Martin's werewolf story "The Skin Trade." I don't remember the whole plot, but I remember the story was *good*. And I don't think this story is available in another book.