This is presently the best available source on design and optimization of particle factories using e e - circular accelerators at the same time giving the physical background for their construction. It addresses scientists and graduate students which is clearly reflected in its pedagogical style. The book aims at summarizing all the currently available knowledge on the motivation to construct particle factories, the design considerations of each of the different machine options including their lattices and interaction regions, practical details of the major systems constituting the machines, as well as a wide view of possible factories worldwide. It is the most up-to-date and unique collection of information of particle factories presently available.