Cennini, Cennino,Craftsman’s Handbook. Dover Publications, ©1978. (Translated fromIl Libro dell’Arte.)  Available from Amazon.com.
Perhaps the definitive work on artist’s methods of the medieval and Renaissance periods, although primarily limited to those as practiced in Italy.

Mayer, Ralph,The Artist’s Handbook of Materials and Techniques. Viking Press, ©1991. Available from Amazon.com. 
Long a standard reference for the practicing artist and art student, with histories of methods and materials, formulas, and sources.

Smith, Ray,The Artist’s Handbook. Knopf, ©1987. Available from Amazon.com. 
An excellent presentation, well organized, and accompanied by clear charts, illustrations and photographs.