Alchemy is the ancient art of transmutation, called by Paracelsus "the spagyric art," a term he devised from the Greek words for "tearing apart" and "bringing together." Broadly speaking, alchemy is concerned with the fundamental principles of change itself, in both the material, mental, and spiritual dimensions. As a material art, alchemy was the precursor to modern chemistry, and was most famously concerned with transmuting base metals into superior precious metals such as gold or silver, as well as the search for a universal elixir capable of producing regenerative youth and immortality. Within the mystical traditions inspired by Hermeticism, alchemy came to be viewed as a metaphoric system of symbols for spiritual processes of transmutation eventually leading to enlightenment.  

Alchemy is heavily influenced by the ancient Egyptian concept of "first matter," which suggests that some divine agency created the world from an original substance known in Latin as Prima Materia, and that all things are ultimately composed of this original substance. Alchemists believed that all things could also be reduced to prima materia by separating and recombining them in order to transmute them into something superior. They also believed that this process of transmutation into superior forms was already taking place throughout the Universe. The goal of the alchemist was to discover the means of accelerating this natural process of perfection, which is inherent in creation.

The alchemical process of transmutation was accomplished using the mysterious "Philosopher's Stone," which was never explicitly described in alchemical texts. In the physical practice of alchemy, the transmutation of base metals was allegedly accomplished by breaking them down into a black formless mass by either melting them down or dissolving them in a bath of mercury, the universal metallic solvent. The metals would then be put through a series of successive transformations that would eventually yield the Philosopher's Stone, the attainment of which was the alchemical Magnum Opus or "Great Work." When added to the alchemist's furnace, the Philosopher's Stone was said to facilitate the rapid transmutation of molten metals into gold. The spiritual alchemical traditions regard the Philosopher's Stone as an instrument of personal transformation, facilitating evolution from a low state of imperfection (symbolized by the base metals) towards a state of perfection symbolized by gold.

A great deal of alchemical knowledge was lost around 290 AD, when the Emperor Diocletian ordered the destruction of Egyptian and Hermetic texts. However, the classical "Emerald Tablet of Hermes" had fortunately found its way into the hands of Arabian alchemists, who continued to practice the art until alchemy eventually found its way back into Europe in the 12th century AD. As alchemy gained popularity in the Western world it ended up replacing and absorbing many of the disappearing mystery traditions from antiquity.

Whether or not alchemists ever produced viable physical gold, many legends proliferated about their successes, and the prospect of obtaining precious metal from inexpensive base materials was highly appealing to many European patrons. Rulers, clergymen and nobles desirous of obtaining riches enlisted many wandering alchemists, including the infamous Johann Georg Faustus, who was sometimes also employed as a diviner and astrologer. Some of these alleged alchemists were undoubtedly mischievous charlatans who enjoyed the favors of their wealthy patrons for as long as they could manage, before either fleeing or being captured and punished. 

Despite being regarded as a disreputable practice in many circles, alchemy continued to thrive in the Western world until the 19th century, when physical alchemy was largely dismissed as a pseudoscience in orthodox circles. However, many alchemists undoubtedly made valuable discoveries in the course of their experiments, making important contributions to the advancement of the sciences of metallurgy, medicine, and chemistry. Modern observers have also pointed out that alchemical concepts such as the Prima Materia and the transmutation of elements are not entirely out of accord with scientific discovery, since different elements are indeed composed of the same subatomic particles, and metals are transmuted continuously inside stars (and, more recently, inside laboratories).  

The spiritual and symbolic practice of alchemy also had a profound impact on Western mysticism and magick. Both medieval and modern Grimoires are heavily influenced by the Hermetic and alchemical concepts of correspondences, and the concepts of achieving enlightenment based on the harmonization of opposing energies. Many psychological and mystical schools of thought have been influenced by the alchemists' belief that all things in creation contain a seed or blueprint of perfection, and that deliberate experimentation can uncover ways to accelerate this evolutionary process. Carl Jung, in particular, made major contributions to the revival of symbolic alchemy as means of synthesizing conscious and unconscious processes during the course of an individual's personal evolution.

In modern times, many people continue to be inspired by the alchemists quest for both worldly and spiritual advancement while studying the mysteries of the Universe and overcoming its challenges.