This is the first book to present the principles of operation of both the Paul and Penning ion traps - powerful experimental devices in which charged particles can be confined indefinitely in a small region of space so that experiments may be performed on them. This new and exciting method has applications not only in atomic physics, frequency standards, and collisional studies, but also in analytical mass spectrometry, making this book highly relevant not only to physicists but also to chemists. Written by a leading authority in the field, it is unique in bringing together detailed information on these two traps, and contains an outstanding bibliography which provides a historical overview to the development of the field.