Helmont was one of the founders of biochemistry. He was the first to realize the physiological importance of ferments and gases, and indeed invented the word “gas”. He introduced the gravimetric idea in the analysis of urine. Helmont published very little during his life. The above work is a collection of his writings, issued by his son, Franz Mercurius, who also worked with the Cabalist scholar/mystic, Christian Knorr von Rosenroth (1636-89) on the expanded German language version (Sulzbach, Endters Söhne, 1683), considered the best edition of the text. English translation from the Latin, London, L. Loyd, 1662. The German edition was reprinted with notes by W. Pagel & K. Kemp, Munich, Kösel, 1971.