Like many of van Vogt's works, throughout the story he gives legends, then garbled truth, and then the full truth... which may or may not actually explain everything, or be entirely consistent with what came before. While this technique tends to enrich the story and make it more realistic, it nonetheless can cause a certain degree of confusion for the reader.
Here, I've set out the most commonly accepted legends about slans and world history and contrasted them with the true history as revealed towards the end of the book.
If history has taught one thing, it's that how people perceive history and the world they live in dictates how they live and treat others. As a result, legends are accepted as fact and people act on them, not knowing their fears and beliefs are baseless. This section discusses these legends and how people acted on them.
For just the straight facts on early slan history, see the Timeline.
It is universally believed that a scientist in the distant past named Samuel Lann used a "mutation machine" on his wife resulting in the birth of the first slan infants. Furthermore, it is believed that the slans themselves continue this practice on regular human women, converting humans babies into their own kind (39, 55, 84, 185-6), with the "failed" conversion attempts being the presumed cause for the vast majority of mutations that occur. The exact opposite is true — it is the mutations that are responsible for the existence of slans (174-5). Most of humanity's hatred of slans arises from this single misinterpretation, jumping to conclusions by mixing up cause and effect.
The majority of people seem confused as to whether slans naturally give birth (slan women are referred to as "breeders" on page 31) or whether they reproduce solely through mutating human babies. For this reason, slan women seem to be more greatly feared than the men (31). Even the tendrilless believed these random mutations to be the failed results of the slans' use of mutation machines (104-5).
Surprisingly for a story dealing with telepathy, the slans' telepathic ability was not the main reason for their persecution. This fear of having their infants "slanized" is consistently stated as the single greatest reason for humanity's fear of slans (28, 30-1, 39, 55). Slans in China were tolerated until the natural mutations began there about 100 years prior to the story (55). According to Petty, slans are still tolerated as fellow humans in the more "primitive" parts of the world, and the more remote areas may harbor secret slan colonies (75-6). Slans were also hated due to their perceived artificiality, as the twisted products of experimentation (40, 85). Petty also expresses mankind's feelings of overall inferiority as the reason why slans must be exterminated (85).
It is commonly believed that the conflict between slans and humans has only lasted a few centuries; the figure usually given is at least 400 years (78). Slans supposedly have existed for "over six hundred years" (84) — in truth, they have been around for almost 1,500 years (185).
The slans' history is very confused: While some were in hiding for centuries and engineered the various slan offshoots (186), others openly tried to conquer the world (5, 43, 56). Also, some secretly controlled the human government in order to keep their augmented offshoots from conquering the world (182) — while at the same time deliberately antagonizing them and making them stronger for the eventual, inevitable final showdown with humanity (187) — while other slans lived in secret refuges that were sought out and destroyed by that very same government (131, 137). And then there were always some stragglers who were never in contact with other slans (183). This disparity can perhaps be explained due to various slan factions being active and ignorant of each other's existence and activities. However, it should be emphasized that these contradictions are not resolved within the novel, leaving it to the reader to ponder and speculate long after he has finished reading it.
Humans believe slans tried to conquer the world (52). Although the facts have been greatly distorted over the years such an attempt was indeed made. This was supposedly done by a mere hundred thousand of them (55). During the time of chaos and upheaval following the mass of natural mutations that began appearing, slans infiltrated numerous vital organizations and took over. Considering the kind and "humanitarian" nature of the slans this was possibly done to restore order, though it was no doubt partially due to Samuel Lann's insistence that his "children" were entitled to rule the world (76, 175). During this war, slans did not use atomic weapons (73). During this time Centropolis was their capital and they built the magnificent palace (5, 43). But when the mutations continued unabated, and indeed only increased, slans were seen as the perpetrators and were overthrown (56).
The bulk of humanity believes that space-flight was never mastered, though there are many legends that parts of the solar system were explored at some time; the government derides these legends as slan propaganda (50). (It's possible that the slans themselves were the ones exploring space — for further discussion, see Timeline: 2100-2200).
Compared with the general population, the government had a more realistic attitude towards slans; they foisted emotional propaganda on the ignorant populace to keep them under control (35, 127). The government saw it as a simple clash between two races, only one of which could be dominant (72), and the slans' innate superiority made it necessary to create a fearful mob mentality among the populace as a counterbalance, to fight the slans through sheer hatred and force of numbers. Although this strategy was effective in a crude fashion, Kier Gray recognized that such a policy had definite major drawbacks in that valuable opportunities were irrevocably lost whenever the mob asserted its unthinking hatred (30). Kier Gray's description of the common citizenry as a "poor, bewildered mass of fools" (35) is quite apt, as they are deliberately fed lies that often contradict each other, and they have a hard time trying to decide what they should believe.
Persecution of slans seem to have been focused mainly in the large urban areas; slans in outlying places were considered too hard to get to and too far from mainstream civilization to pose a serious threat (76). Kier Gray has consistently fed the council and the public the idea that the slans are vastly superior technologically, yet Petty states that they have never seen such gadgets (31). This insinuates that slans are few in number, as well as being well-hidden by this point.
According to the message capsule dropped on the palace, there are 1 million organized slans in the world and an additional 10 million living on their own (75). Since this capsule was created by Gray and his slan associates (183), this information may be false or merely exaggerated; others estimate the number of slans at five million altogether. By comparison, the current population of humans in the story is estimated at 3.5 billion (79).
The standard test administered by humans to detect slans is to remove their head covering to reveal tendrils (59). It therefore became a standard slan practice to routinely wear false hair pieces (120). The tendrilless became aware of this practice and instituted what I call the "toupee test" to check for false hair (166- 7).
All mutations among the human population are routinely killed (presumably at birth) by the medical authorities (113). (This is illustrated quite dramatically in Kevin J. Anderson's novel Slan Hunter.) According to the figures given by Petty, about 100 slans are capture globally on a monthly basis (75). Apparently, most of these captures are done by trapping slans in the hundreds of abandoned slan refuges that are kept under close automated surveillance by the authorities (131). The precautions taken to trap even a single slan are elaborate, including blocking off all highways to a major metropolis (89). Whenever a slan ship is reported near Centropolis, it seems to be common practice for the government to broadcast radio interference to prevent slans from spreading "lies," and attempt to shoot them down with gun emplacements scattered across the city (60).
Through Kier Gray, the slans tried their own counter-propaganda, attempting to assuage mankind's fear of them by posing as less of a threat. Such attempts were universal failures, though the appearance of an obviously sub-standard slan ship did succeed at least in making the tendrilless slans nervous about the true slans' real capabilities and postpone their invasion of Earth (76-7, 183).
Tendrilless slans fear and hate true slans even more than the humans do (95). Slans are called "snakes" by the tendrilless slans (48, 95); this epithet was never used by humans. According to the incomplete and inaccurate knowledge of the tendrilless, their own race has existed for over 400 years (102). They were supposedly a later creation of the same mutation machine that created the true slans (104). In their early days they lived in remote areas to avoid persecution. However, the true slans — with whom they had had no previous contact — attacked the tendrilless communities without mercy, forcing them to flee into the urban centers where they could hide. True slans, since their tendrils were difficult to conceal, rarely ventured into the cities. Because of this, the tendrilless have a definite and concrete reason why they fear and hate true slans — since those days, the tendrilless have killed slans on sight. No contact between the two races has ever been established, and the tendrilless have never come across a single slan community in 300 years (102). This conflict is supposedly racial — according to the tendrilless, some captured slans have said that no variation of the "perfect" slans should be allowed to live (104).
There are undoubtedly millions of tendrilless, far greater in number than true slans. Jommy encountered countless tendrilless slans on his extensive travels on Earth and Mars. On the other hand, the purpose and location of the true slans is the world's greatest mystery (102). The truth is that the true slans are very few in number, the tendrilless having, by design, practically replaced them. But since the tendril gene was designed to lay dormant for quite some time, the tendrilless slans will eventually "become" true slans again (186-7). Apart from the "stragglers," who belong to no slan organization, many of the true slans secretly rule the human government (182-3).
The tendrilless consider the elusive slans the greatest threat to them (145, 165) — even their massive arsenals of ships and weapons were small comfort (161). They had elaborate precautions to detect true slans in their midst — in addition to their large fleets and arsenals, Porgrave thought receivers were rigged to alarm systems throughout their cities (157). Thorough medical examinations were routinely given to individuals matching Jommy's physical description, which included tests on skin, blood, hair, fingerprints, and X-rays (162). After their dealings with Jommy they deduced that the slan organization no longer posed an obstacle and that Jommy himself was more important; they therefore felt free to begin their plan to openly invade Earth (145).