Tuf Voyaging is a science fiction novel by George R. R. Martin, first published in 1986. It is a darkly comic meditation on environmentalism and absolute power, and is regarded by many fans as being among Martin's best early work.
This fix-up novel is a collection of short fiction works published over several years beginning in 1976 with "A Beast for Norn," and did not incorporate the S'uthlam stories (all of which were published in Analog) until late 1985, shortly before the fix-up was collated, given a Prologue, and published in book form. The novel concerns the (mis)adventures of Haviland Tuf, an exceptionally tall, bald, very pale, overweight, phlegmatic, vegetarian, cat-loving but otherwise solitary space trader. Due to the venality and cutthroat tactics of the party chartering his one-man trading vessel, Tuf inadvertently becomes master of Ark, an ancient, 30-kilometer-long "seedship," a very powerful warship with advanced ecological engineering capabilities. Tuf travels the galaxy, offering his services to worlds with environmental problems, and sometimes imposing solutions of his own.
Their destination is a so-called "plague star," known to inflict disease and pestilence on every third generation of a small, remote world. It turns out to be a nearly-derelict seedship of the long-defunct Federal Empire's Ecological Engineering Corps. Tuf's ship, the Cornucopia of Excellent Goods at Low Prices, is damaged by the seedship's automated defenses, and three of the occupants board the seedship by means of pressure suits, while the others left on the ship manage to land it on the seedship.
The halls of the seedship are contaminated with various exotic plagues. One of Tuf's cats dies due to the plagues, and Tuf uses the seedship's capabilities to clone it. In the meantime, the ship's second line of defense is released: monsters from different worlds and ages, including a T. rex. Four of Tuf's passengers die due to the infesting plague, the wandering monsters, or by fighting one another. Rica Dawnstar, in charge of the control room, attempts to kill Tuf, but her plan backfires when Tuf uses one of the crew's leftover weapons and her own aggressiveness to dispose of her.
Due to this, the S'uthlam authorities want the Ark for themselves as both a resource to wring higher calorie production from their star system's biology and as a powerful weapon of war. In an attempt to secure it, Portmaster Tolly Mune kidnaps one of Tuf's cats. She makes a bet with Tuf - if he will solve S'uthlam's impending famine, she will return his cat and give him credit for the ship's repairs. If he loses the bet, S'uthlam will keep the seedship.
Tuf at first reasonably proposes that the S'uthlamese simply restrict their incontinent reproductive practices, but because the S'uthlamese fixation is religious, it is impervious to reason. They will not control their population growth, and thus drive obsessively into a suicidal future of starvation and war.
Tuf works on the problem, and manages to find a solution whereby he uses the seedship's capabilities to provide exotic plants and animals which can provide sustenance for the population. The authorities, with striking proof of the Ark's capabilities, now begin scheming to bring it in their possession. Tolly Mune, disgusted with the politics of the situation, assists Tuf in escaping from S'uthlam, although he informs her that he will return to pay off his debt.
This strategy, initially successful, soon stops working as the monsters gain resistance against these outworldy creatures. Tuf goes back to work, and manages to find a solution. Through his psionically-enhanced cat, he discovers a previously-unsuspected sapient species native to Namor: the mudpots, sessile aquatic bottom-dwellers (which had hitherto been considered dietary delicacies by the Namorian colonists) linked telepathically into a kind of hivemind, controlling the lesser species of life on the planet as skilled bioengineers.
Tuf establishes communications with the mudpots and brokers a peace agreement whereby his human employers agree to cease eating the planet's autochthonous intelligent species. He gives the leaders of Namor psionically-enhanced kittens to facilitate their dealings with the mudpots and departs.
However, paradoxically, the overpopulation crisis has become even worse due to the S'uthlamese people's over-optimistic response to Tuf's Flowering, increasing their reproduction rates. Tuf works on trying to provide even more-efficient crops and animals. He also insists on delivering a planet-wide speech detailing the enhancements he had in mind for S'uthlam and concluding with an explicit admonition.
"The only true and permanent solution is to be found not aboard my Ark, but in the minds and loins of each individual S'uthlamese citizen. You must practice restraint and implement immediate birth control. You must stop your indiscriminate procreation at once!"
This is received with predictable religious outrage, and Tolly Mune is barely able to extract Tuf from the clutches of an angry S'uthlamese mob.
As the House of Norn racks up victories with their cobalcats, Tuf is approached seriatim by the other houses for ever-more-lethally effective beasts (and compatible prey animals), until the greatest of the Houses at last approaches him for a beast and also with a proposal for him to cease all further dealings with the Houses of Lyronica. Tuf graciously accepts the offer.
Herold Norn returns to Tuf to complain about Norn's cobalcats not mating (and about the prey species reproducing without effective suppression and overrunning the Norn lands, making it impossible for the House of Norn to return to breeding their original Arena beasts). Tuf gets the last laugh, as the introduction of the various prey species into each House's territory irrevocably changes the regional ecosystem such that all become incapable of sustaining the large predators upon which the gladitorial contests had originally depended, thus leading to the (unstated) end of the Bronze Arena.
Kreen had attempted to murder Tuf because he blames Moses' plagues upon Tuf, who has gained an interstellar reputation as an ecological engineer, and Tuf realizes that Moses' "plagues" (actually low-tech simulations easily imposed by sabotage upon the closed system of an arcology) offer him an opportunity for revenue.
Kreen is sent down to the planet to bring back the former leaders of the now-conquered and evacuated arcology for negotiations, and Tuf offers to help them against Moses — for a hefty fee. Using the Ark's technology, Tuf introduces himself to Moses as God, in the guise of a pillar of fire. He afflicts the followers of Moses with the bibilical plagues of legend, but these are widespread planetary ecological assaults instead of Moses' fraudulent localized afflictions.
After two such attacks, Tuf invites Moses aboard the Ark and shows him simulations of the increasingly horrible plagues that he could further inflict upon Moses and his followers. Moses, frightened, gives up his claim on the arcology's population, allowing them to escape his nasty, brutish religious fanatacism and return to the comforts of modern civilization.
S'uthlam's population problem remains, worse than ever, as Tuf's innovations from his previous visit were not maximally used. Its society is beginning to break down and either war or social collapse seems likely. Tuf labors to find a solution, and calls a meeting of all the worlds about to clash. He presents to them his solution - an edible, mildly addictive plant called 'manna,' which will freely grow everywhere on S'uthlam and eliminate its hunger problems. After some arm-twisting in which Tuf threatens to use the military might of his seedship against anyone who refuses, the hostile worlds agree to an armistice. Tuf later tells a horrified Tolly Mune that the manna will feed her people, but will also inhibit the libidos of the S'uthlamese and cause widespread - but not universal - sterilization. He leaves Mune to make a momentous decision for S'uthlam; it is implied that she accepts the provision of manna to forestall war and famine.
Eventually this becomes a grim prediction. Finding that most of his clients' problems arise not primarily from true ecological catastrophes but rather as the result of their cupidity, stupidity, bureaucracy, religious fanaticism, and obstinate bloody-mindedness, he resolves their situations by addressing their failings, beginning (1976) with rendering it impossible for the Great Houses of Lyronica to continue the gladitorial animal contests of the Bronze Arena ("A Beast for Norn").
On Namor, he finds a solution - seeking out contact with the previously unsuspected native sapient race - that had escaped the "fighting guild" of unthinkingly truculent Guardians to end the attacks being inflicted upon the human colonists by the planet's mudpot hivemind. On Charity, he copes with both the incompetence of the arcology's administrators ("[Y]ou are by training a bureaucrat," says Tuf to Jaime Kreen, "and thus good for virtually nothing") and the religious tyranny of Moses' Holy Altruistic Restoration.
Finally, in "Manna from Heaven" (1985), he provides the S'uthlamese and their enemies with a solution that simultaneously averts both famine and war but covertly imposes birth control upon the "religious crazies" of S'uthlam's Church of Life Evolving (characterized as "Anti-entropists, kiddie-culters, helix-humpers, genepool puddlers"), forcing Tolly Mune to accept Tuf's induced population implosion as the only alternative to social breakdown and genocide.