Foundations of Alchemical Thought by Heinrich Weyer
Alchemy is, to put it mildly, a science misunderstood by the Isle as whole. Ask your average Arelithian what alchemy is, and no doubt they' mention essences; A concoction based around distilling the vitae of gemstones into oils that will cling to metal and imbue it with power.
Whilst this is an application to the science, it is a base, simple one, and one that avoids the true essence of the study when held up as its magnum opus.
Alchemy is, simultaneously, a philosophy and a science. The science concerns itself with the study of matter and how it changes; That is to say, it is a study of that which makes up everything around us, these objects' base properties, and how these objects and thus these properties change. This study reveals certain ineffible truths, that shape the philosophy of alchemy.
In order to understand Alchemy, you must first understand these truths, first and foremost: All existance is duality. Each of us is the physical elements in some combination: Earth, Fire, Water, and Air. These make up our physical bodies.
Additionally, however, we all have, to some degree, a fifth element: Quintessence. This element provides our Soul, our Mind, our animating force that seperates us from raw stone, or elemental creatures. Quintessence, unlike the other elements is raw on Toril, found primarily within mortal souls/minds, and the Weave; All magic touches upon the anima mundi of quintessence, the eternal "wellspring" whither life is theorized to have sprung from.
The ultimate goal of alchemy is understanding of this Wellspring, of Quintessence and how it relates to the more physical elements. With understanding, so the thought goes, comes the Magnum Opus, the so-called Philosopher's Stone. It is important to note that the Stone is not a physical rock, some substance that grants immortality and control of chrysopoeia.
No, the Magnum Opus is an ascension, a knowledge whose very existance is transative, whose acquisition transforms the knower into a being of pure Quintessence, outside of the ravages of time, and for whom chrysopoeia is a simple, natural and instinctual action, without the requirement of chemical processes.
To this end, to achieve this gnosis, do we imbue the mundane with the supernal.