Acoustics is a major concern in many long spaces, such as road or railway tunnels, underground/railway stations, corridors, concourses and urban streets. The specific problems of such irregularly shaped spaces, ranging from noise pollution in streets and tunnels to poor speech intelligibility of public address systems in railway stations are not dealt with by classic room acoustic theory.This state-of-the-art exposition of acoustics of long spaces presents the fundamentals of acoustic theory and calculation formulae for long spaces as well as giving guidelines for practical design.