In 1972, alien ships orbited close to Earth, sending out mystic vibes that inspired an incredible outpouring of SF across the globe, making this particular anthology an essential vintage. Looking at the award noms for 1973 is like reading a who's-who of classic science fiction, with famous names turning in some of their career's best performances.
The short story is arguably the ideal SF form, and this particular year was a bumper crop. This compilation is an essential for SF enthusiasts, if only because it contains some of the most cited stories in the genre. Top billing goes to Arthur C. Clarke's essential novella "A Meeting with Medusa" which kicks the collection off in fine style, then there's the year's other winners, Poul Anderson's strange and excellent "Goat Song" and feminist SF masterpiece "When it Changed", by Joanna Russ. In addition you get close runner-up "The Fifth Head of Cerberus" by Cordwainer Smith, which is still well thought-of, and an entertaining fantasy in the style of Sam Delaney or Iain Banks. Plus there's big names in the form of Robert Silverberg and Harlan Ellison (neither on top form, sadly) and a rather fantastic and exceptional story called "Patron of the Arts" by William Rotsler, who I've never come across prior to this.
Buy it. No anthology is perfect, but this is close.