Alchemist's Handbook by Frater Albertus

The Alchemist's Handbook has long been considered a modern-day classic on the actual practice of alchemy since its first publication in 1960. The book still stands as a groundbreaking work presenting in clear, concise language a practical manual of working knowledge that was formerly handed down only under oath of secrecy.

The scope of alchemical work is to provide both a means to synthesize all the other sciences and the necessary training of the intellectual and spiritual faculties. "Hermetic philosophy, with its practical arcanum... (it)repeats itself over and over again in the ancient axiom. As above, so below. As below, so above," writes Frater Albertus.

So, if you really want to learn the basic principles of practical alchemy, Frater Albertus' Alchemist's Handbook is literally worth its weight in gold.