This book focuses on the applications of geophysics in addressing rock properties for petroleum geoscience, geotechnical, and geothermal applications. Sophisticated geophysical techniques deliver a fascinating collection of physical data - but they are essentially indirect: information on the velocity of seismic waves, electrical conductivity, nuclear spectra, etc. must be translated in terms of lithology, porosity, fracturing, fluid saturation, permeability, and geomechanical properties. Petrophysical data analysis is one of the key technologies for characterizing reservoirs and for prediction of relevant reservoir parameters using well-log and surface geophysical (seismic) data. Individual chapters cover reservoir properties, petrophysical aspects of NMR, density, electrical, elastic, mechanical, muclear, thermal, and magnetic rock properties. In a special chapter, selected relationships are presented as a foundation for combined interpretation. Presenting the fundamentals of rock physics and combined interpretation techniques, the book may be used as a handbook as well as a textbook for the large community of geoscientists and reservoir engineers.