Book excerpt: Cavitation is a dangerous process which destroys objects in a fluid. Scientific description of this multifaceted phenomenon is based on almost every area of physics, and many interesting effects are connected with cavitation. The most intriguing of them is sonoluminescence – the light emitted from a cavitating fluid. This book presents a full-scale description of cavitation: from the basic thermodynamic principles to special phenomena associated with this complex process, from the dynamics of a single gas cavity to the catastrophic macroscopic manifestations, from the domestic observations to the nuances of X-ray spectroscopic research.