Essential concepts, theory and models of linear acoustics for engineers. This book introduces the basic concepts, theory and models of linear acoustics for engineers. Part one develops the theoretical framework (wave equations, Fourier theory, Helmholtz equation) and introduces key concepts (pressure, velocity, impedance, intensity, power, sound levels). Part two proposes a systematic review of the fundamental physical mechanisms of acoustics and discusses the associated mathematical models: reflection, absorption, resonance, guided propagation, radiation, diffraction, refraction, propagation in dissipative media, convected propagation, atmospheric propagation, fluid-structure interaction, sound transmission and insulation.