Sound-Power Flow: A practitioner's handbook for sound intensity is a guide for practitioners and research scientists in different areas of acoustical science. There are three fundamental quantities in acoustics: sound pressure, sound particle velocity, and sound intensity. This book is about sound intensity and demonstrates the advantages and uses of acoustical sensing compared with other forms of sensing. It describes applications such as: measuring total sound power; directional hearing of humans and mammals; echolocation; measuring sound-power flow in ducts; and uses of non-contact, focused, high-frequency, pulse-echo ultrasonic probes. This book presents computational approaches using standard mathematics, and relates these to the measurement of sound-power flow in air and water. It also uses linear units rather than logarithmic units - this making computation in acoustics simpler and more accessible to advanced mathematics and computing. The book is based on work by the author and his associates at General Motors, the University of Mississippi, and Sonometrics.