excerpts from the introductories:

The Infra-Medians
By Sewell Peaslee Wright

Into a land of shadows and lost
souls goes Pete Grahame in search
of his hapless friends.

There was no sense to the note. There was no sense to anything that Vic Butler did, for that matter. Where he hid away his vast scientific knowledge in that rattle-brained, red-haired head of his has always been a mystery to me. The note read:

Dear Pete:
If you get this, I’m in a jam that promises some action.
Drive out, if plane-peddling is palling on you, and bust into the lab. I’m leaving another note there for you, old son, and after you read it you can let your conscience be your guide.
Bring a gat along, and plenty of ammo. Hope’s away, at Aunt Cleo’s, so don’t get in touch with her and spoil her visit.
-Vic

***

The Whispering Spheres
By R. R. Winterotham

An alien life-form—metallic sinister—threatening
all mankind with annihilation.

CHAPTER I - The Cauldron

The factory saw-toothed the horizon with its hideous profile as the moon rose in the east. The red glow of the furnaces bathed the tall buildings, the gigantic scaffolds, the cord-like elevated pipelines and the columnar smokestacks in the crimson of anger. Even the moon seemed to fade as the long-fingered smokestacks reached toward it belching their pollution. The air, which should have been clean, was filled with the reek of unfamiliar odors.

From the machine shop, where giant cannon were forged into smooth, sleek instruments of death, came noise: unchecked, unmuffled, blasphemous din. But something odd was afoot. There was a sudden hush.

***

Out Around Rigel
By Robert H. Wilson

An astounding chronicle of two Lunarians' conquest of time and interstellar space.

The sun had dropped behind the Grimaldi plateau, although for a day twilight would linger over the Oceanus Procellarum. The sky was a hazy blue, and out over the deeper tinted waves the full Earth swung. All the long half-month it had hung there above the horizon, its light dimmed by the sunshine, growing from a thin crescent to its full disk three times as broad as that of the sun at setting. Now in the dusk it was a great silver lamp hanging over Nardos, the Beautiful, the City Built on the Water. The light glimmered over the tall white towers, over the white ten-mile-long adamantine bridge running from Nardos to the shore, and lit up the beach where we were standing, with a brightness that seemed almost that of day.

"Once more, Garth," I said. "I'll get that trick yet."

***

DAY OF THE MORON
BY H. BEAM PIPER

It's natural to trust the unproven word of the fellow who's "on my side"—but the emotional moron is on no one's side, not even his own. Once, such an emotional moron could, at worst, hurt a few. But with the mighty, leashed forces Man employs now....

There were still, in 1968, a few people who were afraid of the nuclear power plant. Oldsters, in whom the term "atomic energy" produced semantic reactions associated with Hiroshima. Those who saw, in the towering steam-column above it, a tempting target for enemy—which still meant Soviet—bombers and guided missiles...

Scott Melroy was among these last. He knew, as a matter of fact, that there had been several nasty, meticulously unpublicized, near-catastrophes at the Long Island Nuclear Reaction Plant.