This unique book, written by one of the world's foremost specialists in the field, is devoted to the design of low and medium field electromagnets whose field level and quality (uniformity) are dominated by the pole shape and saturation characteristics of the iron yoke.The wide scope covers material ranging from the physical requirements for typical high performance accelerators, through the mathematical relationships which describe the shape of two-dimensional magnetic fields, to the mechanical fabrication, assembly, installation, and alignment of magnets in a typical accelerator lattice. In addition, stored energy concepts are used to develop magnetic force relationships and expressions for magnets with time varying fields.The material in the book is derived from lecture notes used in a course at the Lawrence Livermore National Laboratory and subsequently expanded for the U.S. Particle Accelerator School, making this text an invaluable reference for students planning to enter the field of high energy physics.Mathematical relationships tying together magnet design and measurement theory are derived from first principles, and chapters are included that describe mechanical design, fabrication, installation, and alignment. Some fabrication and assembly practices are reviewed to ensure personnel and equipment safety and operational reliability of electromagnets and their power supply systems. This additional coverage makes the book an important resource for those already in the particle accelerator business as well as those requiring the design and fabrication of low and medium field level magnets for charged particle beam transport in ion implantation and medical applications.