Ultrasonics International 83 contains the proceedings of the Ultrasonics International Conference held in Halifax, Canada, on July 12-14, 1983. The papers focus on the role of ultrasound in various fields such as non-destructive testing, aerospace, high power, and medicine. The papers are organized into 24 sessions, which first discuss the applications of ultrasonics in aerospace. The session on non-destructive testing then describes ultrasonic applications including automatic in-motion inspection of the tread of railway wheels by EMA excited Rayleigh waves; effect of material deformation on the velocity of critically refracted shear waves in railroad rail; and crack depth estimation using wideband laser generated surface acoustic waves. The next session is concerned with medical ultrasonics and includes papers exploring the use of reflectivity tomography in attenuating media, wave propagation in biological tissue, and ultrasonic Doppler measurement of blood flow volume rate in the abdomen. The sessions that follow consider acoustic emission, visualization, material characterization, optoacoustics, and the physics of ultrasonics. High power and underwater ultrasonics, acoustic microscopy, transducers, and instrumentation are also discussed. This monograph will be of value to physicists and other scientists interested in ultrasonics.