Alchemy is a complex and wide-ranging discipline that is difficult to characterize in simple terms. In the course of nearly two millennia, alchemy has appeared in many guises; was formed and reformed by various cultures, ideas, and locales; and was directed toward a variety of goals by its thousands of practitioners. Perhaps the greatest obstacle in gaining an accurate historical understanding of the subject today is the fact that alchemy continues to be misrepresented in many modern accounts. In many quarters, reinterpretations and programmatic reassessments of alchemy that date from the eighteenth to the early twentieth centuries continue to dominate and to be read back onto earlier epochs. Recent scholarship, however, has shown that these latter-day perspectives are historically untenable. Indeed, the past forty years have witnessed a remarkable blossoming of scholarly studies of alchemy, with the felicitous result that we now have access to a vastly more accurate understanding of what alchemy really was at various points in its long history.
A key point to stress at the outset is the internal diversity of alchemy. It is not an unchanging monolithic tradition, although it is sometimes represented as such by both its practitioners and its commentators. This issue becomes especially critical when the question of alchemy's connection to esotericism and mysticism arises. It is true that alchemy can be seen as a “common thread” running through various topics addressed in this volume. Nevertheless, both the degree and the uniformity of those connections are frequently overstated, and their nature misunderstood. The source of the problem is twofold. On the one hand, interpretations of alchemy dating from the Enlightenment and the Victorian era recast the subject into much closer association with topics routinely labeled as “occult” than had ever been the case historically. Thus, many popular treatments of alchemy today, and even some scholarly ones, regularly and rather casually claim that alchemy was “magical,” “spiritual,” “occult,” or “mystical.” The general aim of these characterizations has been to define alchemy as something very distinct from chemistry. By doing so, these accounts perpetuate – often unwittingly – the ahistorical claims of uniquely eighteenth- and nineteenth-century interpretations or reformulations of alchemy.
On the other hand, the terms “mysticism” and “esotericism” tend to be employed in so loose and vague a manner that they sometimes fail to retain any precise or consistent meaning.