This is a highly recommended work on alchemy. Althought it doesn't exactly give away any "secrets" it helps explain much of the worldview of the alchemists of ancient (and modern!) times.

"Of the Means of Arriving at the Secret
The requirements necessary in order to arrive at this Secret, are: the knowledge of Nature and of one's self. One may not understand the first perfectly, or even the second, without the aid of Alchemy. The love of wisdom, the horror of crime, and of falsehood, ... the association of the wise, the invocation of the Holy Spirit; not to add secret to secret, to attach one's self only to one thing (because God and Nature delight in unity and simplicity), such are the conditions necessary for obtaining the divine revelation.
Man being the epitome of all Nature, must learn to know himself as the summary, the miniature of Nature. By his spiritual part he is allied to all immortal creatures, and by his material part, to all that which is transient in the Universe."

- Antoine-Joseph Pernety, who was amongst other things a Benedictine Monk, and Librarian of Frederick the Great, King of Prussia.