Xunzi was born Xun Kuang -- or perhaps Sun Kuang -- but beyond that we know very little about him. He first really shows up in the states of Qi and Qin in his fifties, and is thought to have lived out much of his later life in what would be the modern Shandong province. The most notable figures who are thought to have been his students, Li Si and Han Fei, were important anti-Confucians, so in a sense his tradition dead-ends with him. This is not to say that he did not have influence, since the absolute dominance of Mencian thought in Confucian circles only really arises in the Song dynasty, and the very fact that we have a surviving substantive work from him is a point worth considering. While Xunzi would often be criticized, it is only with the Song commentators that Xunzi becomes treated as a kind of Confucian heresiarch because of his heavy (but entirely Confucian) criticism of Mencius.
As with all the major Confucian texts, it is a matter of considerable controversy how much of the Xunzi text is actually due to Xunzi himself. It consists of thirty-two chapters that stand alone very easily. The text as we have it was compiled in the first century BC by Liu Xiang, who himself says that he started with over three hundred texts and edited it down to thirty-two -- some of those three hundred were duplicates, but we don't know in what proportion, nor do we know for sure what Liu Xiang did in building the thirty-two chapter work we have. For instance, each chapter has a title, but we don't know if all of these are Liu Xiang's or if some of them go back to the beginning. Because of its origin, there is no fixed chapter order, and new editors in new generations felt free to shuffle them around to an order that made more sense to them. Likewise, while some of the chapters would make nice stand-alone essays, others seem to be more miscellaneous chapters in which Liu Xiang put pieces he couldn't fit elsewhere, and the 'smoothness' of the chapters varies considerably. Without Liu Xiang's original sources, it is impossible to say how much of the text actually goes back to Xunzi himself; some of it, or even most of it, could be due to lesser known or unknown disciples. On the other side, though, there is no reason to think that the book is in any way unfaithful to Xunzi's thought, either.
The translation I will be using is that of Eric L. Hutton, who follows the most common chapter order, that of Yang Liang. David Elstein has a nice overview article on Xunzi at the Internet Encyclopedia of Philosophy, and Dan Robins another such overview article at the Stanford Encyclopedia of Philosophy.
I. Quanxue (An Exhortation to Learning)
"Learning must not stop" (p. 1), that is to say, a constant state of refinement and improvement is necessary to life of the junzi, or noble. Learning as Xunzi conceives it is essential social: by building on the work of others you are able to go farther than you would be able to go on your own. This will tie in with one of Master Xun's constant themes: greatness and authority are not things you simply have, any more than you have a good view simply by your birth, but must be worked at. To have a good view, you must find a good place to stand. It matters where you live and with whom you associate. As he will say later, "In learning, nothing is more expedient than to draw near to the right person" (p. 6).
Learning likewise is a matter of slow accumulation. It is by small steps that you reach a destination worth reaching, and it is important for the process of accumulation not to give up simply because things get tedious or difficult. One starts with the classics, moves on to the study of ritual, and never stops until death. It must be upheld at all times: "To pursue it is to be human, to give it up is to be a beast" (p. 5).
The noble do not merely receive learning; they assimilate it. It sticks in their heart, diffuses through their body, is expressed in their action, so that everything they do is an expression of what they have learned and thus a model for others. The petty, Master Xun says in a striking image and joke, are such that learning enters their heart and leaves their mouth: "From mouth to ears is only four inches--how could it be enough to improve a whole body much larger than that?" (p. 5). Learning should be for improvement of self, not for impressing others.
The result is a very high standard. People who are inconsistent in their principles and actions are not to be trusted as teachers; only those who pursue important things wholeheartedly have a true grasp on learning, and thus are able to pass along in a proper way things they have learned. The noble person, then, will devote himself without qualification to learning, knowing that the flawed does not deserve praise.
II. Youshen (Cultivating Oneself)
Education is fundamentally a matter of self-education, and this means that all things are occasions for education. If you see goodness in another, look to see how you can cultivate it; if you see badness in another, look to see if you are guilty of or in danger of it. One should avoid flatterers, who may mislead you, and you should regard your critics, when right, as more friends than your supporters who support you no matter what. This is one of the distinctions between the noble and the petty.
Teaching has a necessary relation to what is good; it is contrasted with leading others to what is bad, which is flattery. (The argument here is quite similar to that of Plato in the Gorgias.) Education is thus by its nature practical: there are specific remedies to handle problems so that, for example, if you are sluggish or greedy, you need to cultivate "lofty intentions" (p. 11). This practicality means that your self-cultivation should proceed regardless of whether your situation is difficult or not (the farmer does not become more lazy in times of drought), and you need to have a good template or model to follow, which you then must proceed to use in a way appropriate to it.
Rituals are ways of correcting yourself; "to contradict ritual is to be without a proper model" (p. 14). We rely on teachers to help us to correct our implementation of them.
III. Bugou (Nothing Improper)
The noble only esteem what is in accordance with ritual and rightness. It is precisely this that guarantees that the noble man is consistently good and admirable, regardless of what temperamental or acquired traits he may have. Whether the noble are learned or unlearned, cautious or ambitious, renowned or in obscurity, pleased or displeased, wealthy or poor, the noble are in accordance with ritual and rightness. The petty are the opposite; they are discordant and sowers of discord whether they are learned or unlearned, cautious or ambitious, renowned or in obscurity, pleased or displeased, wealthy or poor:
A saying goes, "In both cases the gentleman advances. In both cases the petty man falters." This expresses my meaning. (p. 18)
The noble cultivate themselves by cheng, being true to their proper nature. Because the noble man is steadfast and consistent he becomes an element of the environment, so to speak; and just as heaven and earth and the seasons have their effects without having to use words, so the noble person teaches and improves the world simply by living nobly.
In making decisions, one must be balanced and thorough, looking at everything from each side in order to determine what is desirable or undesirable. Failure to do this may lead to an appearance of propriety or nobility that is purely an illusion.