Practical Casting by Tim McCreight: A Studio Reference
Probably the best and most complete text on small-scale casting. Excellent explanations and illustrations.
This popular volume features detailed illustrations, a complete listing of sources and a compact, no-nonsense style that will let you spend your time working rather than looking for information.
Tim McCreight is one of the nation's best known metalsmiths/jewelers. His book, The Complete Metalsmith, has sold over 100,000 copies.