Before his untimely death in 1971, August Derleth, already acclaimed for editing numerous SF anthologies, selected the contents for a final "retrospective" gathering of first rate, exemplary SF tales, but never completed the project. Now, with an Introduction and Authors' notes provided by Joseph Wrzos, "New Horizons" finally appears. Among the now celebrated pulp SF authors represented are Murray Leinster, Clark Ashton Smith, Donald Wandrei, and Frank Belknap Long. As a special feature, the contents include "The Countries of the Sea, " a newly discovered SF novelette by August Derleth and Mark Schorer, published for the first time.