So once again Gentry Lee is commuting across the Pacific for brainstorming sessions in the Sri Lankan hills, and the postman is complaining about the bulky printouts he has to balance on his bicycle. This time around, however, technology has speeded up our intercontinental operations. The fax machine now allows us to exchange ideas almost in real time; it’s far more convenient than the Electronic Mail link Peter Hyams and I used when scripting 20!0 (see The Odyssey File),

There is much to be said for this kind of long-distance collaboration; if they are too close together, co-authors may waste a lot of time on trivia. Even a solitary writer can think of endless excuses for not working; with two, the possibilities are at least squared.

However, there is no way of demonstrating that a writer is neglecting his job; even if his snores are deafening, his subconscious may be hard at work. And Gentry and I knew that our wildest excursions into literature, science, art, or history might yield useful story elements.

For example, during the writing of Rama II it became obvious that Gentry was in love with Eleanor of Aquitaine — don’t worry, Stacey, she’s been dead for 785 years — and I had to tactfully dissuade him from devoting pages to her amazing career. (If you wonder how E of A could have the remotest connection with interstellar adventures, you have pleasures in store.)

I certainly learned a lot of French and English history from Gentry that they never taught me at school. The occasion when Queen Eleanor berated her son, the intrepid warrior-king Richard the Lion Heart in front of his troops for failing to produce an heir to the throne must have been one of the more piquant moments in British military history. Alas, there was no way we could work in this gallant but gay Corleone, who was often a godfather, never a father… very unlike Gentry, whose fifth son arrived toward the end of Rama II.

But you will meet Gentry’s most cherished creation, the yet-to-be-born St. Michael of Siena. One day, I am sure, you’ll encounter him again, in books that Gentry will publish under his own name, with the minimum of help or hindrance from me.

As I write these words, we’re just coming up to the midway point of our four-volume partnership. And though we think we know what’s going to happen next, I’m sure the Ramans have quite a few surprises in store for us…

 — Arthur C. Clarke

The great radar pulse generator Excalibur, powered by nuclear explo­sions, had been out of service for almost half a century. It had been designed and developed in a frantic effort during the months following the transit of Rama through the solar system. When it was first declared operational in 2132, Excalibur’s announced purpose was to give Earth ample warning of any future alien visitors: one as gigantic as Rama could be detected at inter­stellar distances — years, it was hoped, before it could have any effect on human affairs.

That original commitment to build Excalibur had been made even before Rama had passed perihelion. As the first extraterrestrial visitor rounded the sun and headed out toward the stars, armies of scientists studied the data from the only mission that had been able to rendezvous with the intruder.

Rama, they announced, was an intelligent robot with absolutely no interest in our solar system or its inhabitants. The official report offered no explana­tions for the many mysteries encountered by the investigators; however, the experts did convince themselves that they understood one basic principle of Raman engineering. Since most of the major systems and subsystems en­countered inside Rama by the human explorers had two functional backups, it appeared that the aliens engineered everything in threes. Therefore, since the entire giant vehicle was assumed to be a machine, it was considered highly likely that two more Rama spacecraft would be following the first visitor.

But no new spaceships entered the solar neighborhood from the empty reaches of interstellar space. As the years passed the people on Earth con­fronted more pressing problems. Concern about the Ramans, or whoever it was that had created that drab cylinder fifty kilometers long, abated as the lone alien incursion passed into history. The visit of Rama continued to intrigue many scholars, but most members of the human species were forced to pay attention to other issues. By the early 2140s the world was in the grip of a severe economic crisis. There was no money left to maintain Excalibur. Its few scientific discoveries could not justify the enormous expense of assur­ing the safety of its operation. The great nuclear pulse generator was aban­doned.

Forty-five years later it took thirty-three months to return Excalibur to operational status. The primary justification for the refurbishment of Excali­bur was scientific. During the intervening years radar science had flourished and produced new methods of data interpretation that had greatly enhanced the value of the Excalibur observations. As the generator again took images of the distant heavens, almost nobody on Earth was expecting the arrival of another Rama spacecraft.

The operations manager at Excalibur Station did not even inform his supervisor the first time the strange blip appeared on his data processing display. He thought it was an artifact, a bogey created by an anomalous processing algorithm. When the signature repeated several times, however, he paid closer attention. The manager called in the chief Excalibur scientist, who analyzed the data and decided the new object was a long period comet. It was another two months before a graduate student proved that the signa­ture belonged to a smooth body at least forty kilometers in its longest dimen­sion.

By 2179 the world knew that the object hurtling through the solar system toward the inner planets was a second extraterrestrial spacecraft. The Inter­national Space Agency (ISA) concentrated its resources to prepare a mission that would intercept the intruder just inside the orbit of Venus in late February of 2200. Again the eyes of humanity looked outward, toward the stars, and the deep philosophical questions raised by the first Rama were again debated by the populace on Earth. As the new visitor drew nearer and its physical characteristics were more carefully resolved by the host of sensors aimed in its direction, it was confirmed that this alien spacecraft, at least from the outside, was identical to its predecessor. Rama had returned. Man­kind had a second appointment with destiny.

The bizarre metallic creature inched along the wall, crawling up toward the overhang. It resembled a skinny armadillo, its jointed snail body covered by a thin shell that curled over and around a compact grouping of electronic gadgetry astride the middle of its three sections. A helicopter hovered about two meters away from the wall. A long flexible arm with a pincer on the end extended from the nose of the helicopter and just missed closing its jaws around the odd creature.

“Dammit,” muttered Janos Tabori, “this is almost impossible with the “copter bouncing around. Even in perfect conditions it’s hard to do precision work with these claws at full extension.” He glanced over at the pilot. “And why can’t this fantastic flying machine keep its altitude and attitude con­stant?”

“Move the helicopter closer to the wall,” ordered Dr. David Brown.

Hiro Yamanaka looked at Brown without expression and entered a com­mand into the control console. The screen in front of him flashed red and printed out the message, command unacceptable. insufficient toler­ances. Yamanaka said nothing. The helicopter continued to hover in the same spot.