The book is divided into 12 chapters, first five chapters cover the kinetic theory of gases and the rest seven are devoted to waves and acoustics. First chapter is ideal gas covering the kinetic model of ideal gas, gas laws, degrees of freedom, law of equipartion of energy, barometric equation. Chapter two is about viscosity, thermal conductivity, diffusion and their relationship. Chapter three is related to real gases covering Van der Waals' equation, critical constants and porous plug experience etc. Chapter four is liquefaction of gases giving the methods of cooling of gases. Chapter five is Maxwell's law of distribution of speed and velocity of gases. Chapter six is wave equation and waves in string, solid and in gaseous medium. Chapter seven and eight are related to superposition of waves and the standing waves and vibrations in bounded media. Chapter nine gives as idea about the ultrasonic waves. Musical instrument and characteristic of sound are discussed in chapter ten. Chapter 11 is for reflection and diffraction of sound waves and the last chapter is applied acoustics.