Along with Astounding Science Fiction and The Magazine of Fantasy and Science Fiction, Galaxy Magazine was one of the most important science fiction digests in 1950s America. Ray Bradbury wrote for it–including an early version of his masterpiece Fahrenheit 451–as did Robert A. Heinlein, Isaac Asimov, Frederik Pohl, Theodore Sturgeon, Cordwainer Smith, Jack Vance, and numerous others.
Now a fairly decent collection of issues (355 in total) is available for your perusal at archive.org for absolutely free. It’s not complete yet, but it’s close.
If you are even a casual fan of science fiction, you’ve got to check out some of these issues. The writing can seem dated at times but you’ll still enjoy some great sci-fi.