This volume presents the latest ideas and developments in the world of beam diagnostics in particle accelerators and storage rings. It brings together papers by internationally recognized experts and by the younger scientists in the field. The lectures treat three main themes: - Phenomena used in beam observation - Single particle parameters - Collective parameters Each theme is introduced by one or more general lectures followed by detailed lectures on specific topics such as Schottky noise, closed orbits and impedance measurements. The overall aim was to show how to observe the diverse behavior of a beam, how to interpret and classify the observations and then how to control or correct the relevant parameters. The resulting volume contains much of the information needed to operate or commission a machine. The lecture program was supplemented by three seminars that looked at monitoring in e+e- colliders and at the special problems of nonplanar machines and experimental particle tracking. This unique and comprehensive collection of papers is the most up-to-date presently available.