Back in the 1950s, I wrote a series of six derring-do novels about David "Lucky" Starr and his battles against malefactors within the Solar System. Each of the six took place in a different region of the system, and in each case I made use of the astronomical facts-as they were then known.

Now, a quarter-century later, Fawcett is bringing out the novels in new editions; but what a quarter-century it has been! More has been learned about the worlds of our Solar System hi this last quarter-century than in all the thousands of years that went before.

LUCKY STARR AND THE RINGS OF SATURN was written in 1957, but in 1967, a French astronomer, Audouin Dollfus, discovered a tenth satellite of Saturn, one that was closer to the planet than any of the others, 22,000 miles closer to Saturn than Mimas is. This new satellite has been named Janus.

If I were writing the book today, I would certainly mention that satellite and I might have used it instead of Mimas.

Moreover, it was not until 1977 that astronomers discovered that Saturn was not the only ringed planet. Uranus, it turns out, also has rings. They are very thin rings and very faint ones-but they're there. I would surely have mentioned that in this book if I were writing it today.

I hope my Gentle Readers enjoy the book anyway, as an adventure story, but please don't forget that the advance of science can outdate even the most conscientious science-fiction writer and that my astronomical descriptions are no longer accurate in all respects.

Isaac Asimov

The Sun was a brilliant diamond in the sky, just large enough to the naked eye to be made out as something more than a star; as a tiny white-hot pea-sized globe.

Out here in the vastness of space, near the second largest planet of the Solar System, the Sun gave out only one per cent of the light it cast on man's home planet. It was still, however, the brightest object in the sky, as four thousand full Moons would be.

Lucky Starr gazed thoughtfully at the visiplate which centered the image of the distant Sun. John Bigman Jones watched with him, an odd contrast to Lucky's tall and rangy figure. When John Bigman Jones stretched himself to his full height, he stood five foot two exactly. But the little man did not measure himself in inches and he allowed people to call him by his middle name only: Bigman.

Bigman said, "You know, Lucky, it's nearly nine hundred million miles away. The Sun, I mean. I've never been out this far."

The third man in the cabin, Councilman Ben Wes-silewsky, grinned over his shoulder from his place at the controls. He was another large man, though not as tall as Lucky, and his shock of yellow hair topped a face that had grown space-brown in the service of the Council of Science.

He said, "What's the matter, Bigman? Scared way out here?"

Bigman squawked, "Sands of Mars, Wess, you get your hands off those controls and say that again."

He had dodged around Lucky and was making for the Councilman, when Lucky's hands came down on Bigman's shoulders and lifted him bodily. Big-man's legs still pumped, as though carrying him toward Wess at a charge, but Lucky put his Mars-born friend back in his original position.

"Stay put, Bigman."

"But, Lucky, you heard him. This long cobber thinks there's more to a man just because there's more of him. If that Wess is six feet tall, that just means there's an extra foot of flab… "

"All right, Bigman," said Lucky. "And, Wess, let's save the humor for the Sirians."

He spoke quietly to both, but there was no questioning his authority.

Bigman cleared his throat and said, "Where's Mars?"

"On the other side of the Sun from us."

"Wouldn't you know," said the little fellow disgustedly. Then, brightening, "But hold on, Lucky, we're a hundred million miles below the plane of the Ecliptic. We ought to be able to see Mars below the Sun; peeking out from behind, sort of."

"Uh-huh, we should. Actually, it's a degree or so away from the Sun, but that's close enough for it to be drowned out in the glare. You can make out Earth, though, I think."

Bigman allowed a look of haughty disgust to cross his face. "Who in space wants to see Earth? There isn't anything there but people; mostly groundhogs who've never even been a hundred miles off the surface. I wouldn't look at it if that were all there was in the sky to look at. You let Wess look at it That's his speed."

He walked moodily away from the visiplate.

Wess said, "Hey, Lucky, how about getting Saturn on and taking a good look at it from this angle? Come on, I've been promising myself a treat."

"I don't know," said Lucky, "that the sight of Saturn these days is exactly what you might call a treat."

He said it lightly, but for a moment silence fell uneasily within the confined pilot room of The Shooting Starr.

All three felt the change in atmosphere. Saturn meant danger. Saturn had taken on a new face of doom to the peoples of the Terrestrial Federation. To six billion people on Earth, to additional millions on Mars, the Moon, and Venus, to scientific stations on Mercury, Ceres, and the outer moons of Jupiter, Saturn had become something newly and unexpectedly deadly.

Lucky was the first to shrug off that moment of depression, and, obedient to the touch of his fingers, the sensitive electronic scanners set into the hull of The Shooting Starr rotated smoothly on their universal gimbals. As that happened, the field of vision in the visiplate shifted.

The stars marched across the visiplate in steady procession, and Bigman said with a curl of hatred in his upper lip, "Any of those things Sirius, Lucky?"

"No," said Lucky, "we're working through the Southern Celestial Hemisphere and Sirius is in the Northern. Would you like to see Canopus?"

"No," said Bigman. "Why should I?"

"I just thought you might be interested. It's the second brightest star and you could pretend it was Sirius." Lucky smiled slightly. It always amused him that the patriotic Bigman should be so annoyed because Sirius, home star of the great enemies of the Solar System (though themselves descendants of Earth-men), was the brightest star in Earth's heavens.

Bigman said, "Very funny. Come on, Lucky, let's see Saturn, and then when we get back to Earth you can get on some comedy show and panic everybody."

The stars kept their smooth motion, then slowed and stopped. Lucky said, "There it is-unmagnified, too."

Wess locked the controls and twirled in the pilot's seat so that he might see also.

It was a half-moon in appearance, somewhat bulging into more than half, just large enough to be seen as such, bright with a soft yellow light that was dimmer in the center than along the edges.

"How far away are we?" Bigman asked in astonishment.

Lucky said, "About a hundred million miles, I think."

"Something's wrong," Bigman said. "Where are the rings? I've been counting on a good look."

The Shooting Starr was high above the south pole of Saturn. From that position it should see the rings broad on.

Lucky said, "The rings are blurred into the globe of the planet, Bigman, because of the distance. Suppose we magnify the image and take a closer look."

The spot of light that was Saturn expanded and stretched in every direction, growing. And the half-moon that it had seemed to be broke up into three segments.