Mid-century vintage, 1940s pulp science fiction magazine, "Astounding Science Fiction" from March, 1949. The cover story for this issue is "Missing Ingredient", by Alejandra. There are also stories by L. Sprague de Camp, Wilmar H. Shiras and others.
This is in nice vintage condition. We don't know anything about grading pulp magazines, but this issue does have light wear and age. There is a "3 9" in ink on the bottom edge of the pages.