Ground Penetrating Radar: Theory and Practice is a practical guide to using this powerful underground surveying technique. The author uses her wide experience to explain the critical factors in using GPR and how parameters, such as wavelength, attenuation and loss need to be properly considered to obtain good survey results. The first chapter introduces the underlying physics and explains the formation of signal patterning. The next two chapters explain the significance of wavelengths for target detection, probing depths and resolution, and demonstrating the variety of signal presentations. Chapter four discusses why survey results are affected by water and air in the soil, and how this may affect depth readings. Additional chapters discuss a variety of methods for velocity calibration and suggest where they may be useful, challenging soil conditions and potential problem environments, data processing, and a suite of useful techniques, amongst other important topics.