Electroforming is a process which, by definition, produces parts and is not to be confused with electroplating which provides only a final finish on otherwise produced parts. The implication can immediately be drawn that the electroformer must have far broader knowledge than an electroplater. The supervising electroformer should not only be an expert in the field of electrochemistry, but should also be proficient in mechanical engineering, metallurgy, art, and a host of other fields that could include microwave engineering, since electroforming is being called upon more and more to produce the increasingly accurate and complex waveguides required in radar and microwave communications equipment. This broad scope of proficiency is necessary because an electroform can only be as good as the mandrel, master, or matrix from which it is formed. The electroformer must be prepared properly to design and produce masters that will best serve each particular requirement. The electroformer could be of far greater usefulness to industry if product designers better understood the present state of the electroforming art. New possibilities are constantly being discovered through more intelligent and versatile use of materials and methods for masters, mandrels, and matrices. There follows a discussion of the three basic types of masters, the advantages and disadvantages of each, the variations of each type, and the problems which remain to be solved.