This text aims to cover all details of the subject of design, from the faces to deflection of the rings. It provides a complete mathematical treatment which can be used as the basis for design programmes, or the student can use some of the programmes provided in the book for experimentation. The mathematical treatments are supplemented with examples and practical advice, and examples of seals are also given. The text provides background detail in many special areas which can be used as a base for special projects or investigations by the student.