The Golden Age of SF is universally dated from the July 1939, issue of Astounding because that's when "Black Destroyer," A. E. van Vogt's first SF story, appeared. Isaac Asimov's first story also appeared in the same month but nobody—as Asimov himself admits—noticed it.
People noticed "Black Destroyer," though, and they continued to notice the many other stories that van Vogt wrote over the following decade. With the encouragement and occasionally the direction of John W. Campbell, Heinlein, deCamp, Hubbard, Asimov, and van Vogt together created the Golden Age of SF.
Each of those great writers was unique. What as much as anything set van Vogt off from other SF writers (of his day and later) was the ability to suggest vastness beyond comprehension. He worked with not only in space and time, but with the mind.
Van Vogt knew that to describe the indescribable would have been to make it ludicrous, and that at best description turns the inconceivable into the pedestrian. More than any other SF writer, van Vogt succeeded in creating a sense of wonder in his readers by hinting at the shadowed immensities beyond the walls of human perception. What we've tried to do in our selections for Transgalactic is show some of van Vogt's skill and range; but we too can only hint at the wonders of the unglimpsed whole.
Eric Flint and Dave Drake 2005