This volume comprises the proceedings of the 8th Joint School on accelerator physics. On this occasion, the US, CERN, Japan and Russia Particle Accelerator Schools collaborated to present the topic of "Beam Measurements". The aim was to provide an introduction to the principles of beam dynamics and measurements in circular particle accelerators. This was achieved by a series of lectures under the headings of "single-particle dynamics", "multi-particle dynamics" and then "beam measurements", along with practical courses on feedback and signal processing, maps and (no) simulations, practical diagnostic measurements, and spectrum and network analyzers. The resulting proceedings represent a unique summary of the currently available knowledge on beam measurements applied to circular particle accelerators.