Von Stahel und Eysen (English: On Steel and Iron) is the first printed book on metallurgy, published in 1532 by several publishers: Kunegunde Hergot in Nuremberg, Melchior Sachs in Erfurt, and Peter Jordan in Mainz.
Nu spricht meister Alkaym' in the late fourteenth- or early fifteenth-century Nuremberg manuscript Nürnberger Handschrift GNM 3227a.
[1] About half the text is on how to harden iron and steel through tempering and quenching, mentioning water, but also a range of recipes of varying degrees of elaborateness.
[3] A modern commentator on some of the more outlandish techniques in the book noted: "There isn't really much to say...except that perhaps it was meant to trip up rivals.
Etching was quite a new technology at the time, and Von Stahel und Eysen provides the first attested recipes.