In this book, we proposed velocity-free localization methods for acoustic and microseismic sources. This method does not require predetermination of wave velocity, which is a dynamically adjusted free real-time parameter. These methods solve the problem of large localization error caused by the difference between measured wave velocity and actual wave velocity in the source area and greatly improve the positioning accuracy.They are suitable for complex structures where the wave velocity changes dynamically in time and space, such as mines, bridges, buildings, pavements, loaded mechanical...