This is a great collection of action short stories by Algis Budrys from "The Golden Age of Science Fiction". Featured here: "Firegod", "Wall of Crystal, Eye of Night", "Citadel", and "The Rag and Bone Men".
Algirdas Jonas "Algis" Budrys (January 9, 1931 – June 9, 2008) was a Lithuanian-American science fiction author, editor, and critic. He was also known under the pen names Frank Mason, Alger Rome (in collaboration with Jerome Bixby), John A. Sentry, William Scarff, and Paul Janvier. He is known for the influential 1960 novel Rogue Moon.