What prompted the first emperor of Qin to have hundreds of scholars buried alive and their works burned? If history was the primary concern, what interpretations and narratives was he trying to suppress? Was live burial a "normal" punishment or an exceptional one, to make an example?

There are several points to consider here, and I will try to cover them one by one.

First, the general idea of live burial was not an invention of the First Emperor. More than 1,200 sacrificial burials dating to the Shang dynasty have been excavated at Xibeigsang alone, and these include "a few children who seem to have been trussed up and buried alive." A second set of live burials – both men and women – dating to the Warring States period has been uncovered at Langjiazhuang. This type of burial is termed "human offerings" by Chinese archaeologists, as distinct from the "companions in death", typically young women, who were dignified with their own burials. Both types of burial seem to have involved the executions of wives, slaves or attendants who were to accompany some eminent dynast or court official into the afterlife.

In addition, Chinese chronicles record that during the latter years of the Warring States period, not long before the First Emperor's birth, the survivors of a Zhao army that had invaded the state of Qin, but been surrounded and starved into submission, were supposedly "buried alive" en masse by Bo Qi (AKA Bao Qi), the military genius who played a major part in setting up the eventual victory of Qin and the First Emperor over its rival states [Cambridge History of Ancient China I, 193, 640, 734].

This is the closest we get to an example of burial alive apparently being used as an exemplary punishment before Qin Shihuangdi's time, but there is a vitally important caveat that applies both to Bo Qi's atrocity and the deaths of 460 scholars in 212 BC that Sima Qian records, in his the Records of the Grand Historian, were ordered by the First Emperor. This relates to the correct way to translate "k'eng", the word use to describe the deaths of both the scholars and the men of the defeated Zhao army. In its noun form, k'eng means "pit" and it is for this reason that it has been understood since at least the 16th century to mean "buried" or even "buried alive." However, both Emmanuel-Edouard Chavannes and Timoteus Pokora have convincingly argued that it should be translated to mean only "to destroy" or "to put to death"; hence there has to be considerable doubt as to whether any scholars were buried alive in the First Emperor's reign at all. This is not an insignificant point, since the extreme nature of the punishment is integral to the way in which the First Emperor has typically been viewed both by later Chinese chroniclers (who of course could readily imagine themselves suffering similar fates) and by modern historians. [Chavannes, Les Mémoires historiques de Se-ma Ts'ien traduits et annotés, II, 119; for Pokora's views see Archiv Orientální 31 (1963), 170-1.]

Second, if we go back to the works of Sima Qian, it becomes clear that the idea of burning books, if not that of executing scholars, was not the First Emperor's, but rather a policy that was urged on him by his chancellor and chief advisor Li Si (Li Ssu in the old Wade-Giles system of transliteration).

The sequence of events as set out by Sima Qian is that a number of Confucian "scholars of wide learning" attended an imperial banquet held at Qin Shihuangdi's palace in 213. One of these dared to criticise the Emperor for not following the example of Shang and Zhou emperors in giving fiefs to his sons and to "meritorious ministers," a policy that, it was intimated, was crucial to the maintenance of these earlier dynasties. Li Si responded angrily that the "stupid literati" did not understand that things had changed and that "now the world has been pacified, laws and ordinances issue from one source alone." Criticism of "the present age" would only "confuse and excite the ordinary people," leading to a decline in imperial power. "It is expedient that these [criticisms] be prohibited," he concluded.

The practical upshot of Li Si's recommendation was an order that all the relevant records in the imperial record bureau be burned, that any public discussion of the two most important, the poems of the Book of Songs and the chronicles and collections of speeches contained in the Book of Documents, be punishable by death. Furthermore, Li Si urged that orders be given that all copies of the prohibited works that existed outside the immediate control of the imperial government be burned within 30 days.

This order applied specifically to works of history, custom and law. Works relating to divination, agriculture, medicine and forestry were excluded from the edict. Moreover, even copies of the forbidden works were authorised to be preserved within the archives of the Bureau of Academicians. The purpose of the order that interests you, therefore, was explicitly to prevent unrest and not to utterly destroy knowledge, nor, as is sometimes supposed, to establish a Pol Pot style "Year Zero" for a new period of Chinese history, beyond which future historians would not be able to penetrate. It was possession and discussion of the forbidden works by scholars who were beyond the immediate control of the state (unlike those manning the Bureau of Academicians) that Li Si really objected to.

Most scholars suppose that the edict remained in place for no more than about five years (though it was not formally rescinded until 191) and hence that the loss and destruction of old texts was less than total. Nonetheless, if only by drastically limiting the number of copies of ancient works that actually survived, the impact of the decree was considerable. Many of the archived works would have been destroyed when Han armies burned the Qin palaces at Xianyang in 206 BC. It's worth pointing out, however, that this sort of attrition has been a normal feature of Chinese history. We have a catalogue of the Han imperial library as it existed in the first years of the first century (more than two hundred years after the First Emperor's time), for example; of the 677 works listed, three-quarters are now lost to us.

As for the "execution of the literati": that took place one year after the infamous burning of their books and, according to Sima Qian, for a different reason. Its proximate cause was the First Emperor's infamous determination to keep his movements hidden, which the Grand Historian attributed to the advice of the magician Master Lu, who was brought in to assist the Emperor in his search for an elixir of immortality. One consequence of this was that the emperor would have anyone known to have revealed his whereabouts put to death.

On one visit to the east coast, Qin Shihuangdi was angered to note the large numbers of carriages and attendants surrounding Li Si – these, he felt, clearly represented a risk that his whereabouts would be disclosed and the magical forces needed to secure the desired elixir dissipated. This news reached the ears of the chancellor, who, fearing the Emperor's wrath, took immediate steps to reduce their numbers. When Qin Shihuangdi realised that there had to be an informer among his attendants, he had the entire group who had been with him at the time executed.

This drastic action, in turn, prompted unrest among Master Lu and the scholars who associated with him. Lu and several other magicians clearly feared they might be next and fled – taking with them the Emperor's chief hope of attaining eternal life. Qin Shihuangdi ordered an immediate inquiry into how and why Lu and his helpers had been able to flee, and when the other scholars in his entourage blamed one another, he had 460 of them selected for execution. In this case, therefore, the "scholars" we hear so much about were likely Daoists, alchemists and magicians rather than court historians or academics.

[Main sources for the discussion above: Derek Bodde, "The state and empire of Ch'in," in The Cambridge History of China I, 69-72; Frances Wood, The First Emperor of China pp.40-5, 78-88.]

With regard to the follow-up question on sources: Sima Qian's Records are indeed the most significant resource for the reign of the First Emperor. They are important not only because they are the only detailed source we have for much of what happened, but because they were compiled free of much of the inbuilt bias that bedevils later Chinese historiography. As the Cambridge History of China puts it (I, 972):

As yet they were not bound by the inhibitions under which their successors labored. They were not required to display their masters as paragons of fine behavior, whose predecessors had rightly deserved destruction. As yet they were not obliged to portray the past in terms of the steady influence exerted on mankind by the force of Confucian teaching.

[Such characteristics first emerged with full force in histories of the remarkable usurper Wang Mang, whose highly controversial reign at around the time of Christ separates the Former from the Late Han; I discuss these problems in more detail here.]

Two other important sources do exist, however. The first is the Han su or Book of Han, a chronicle of the Former Han Dynasty, modelled on the style established by Sima Qian and covering the period 206 BC to AD 5 in 12 volumes. This work is late - completed c. AD 111 - but its early coverage deals with the overthrow of the Qin dynasty and some of the people who figure in it were important in the First Emperor's reign.

The second source that needs to be considered is archaeological and numismatic evidence – most obviously the imperial tomb from which the famous Terracotta Warriors have been unearthed, but also numerous lesser archaeological sites – most notably record steles – and coin finds.

Good sources of detailed information on the historiography of the period include Van der Loon's "The ancient Chinese chronicles and the growth of historical ideals," in Beasley & Pulleyblank's Historians of China and Japan, and Michael Loewe [ed], Early Chinese Texts: A Bibliographical Guide.