This book has been written to educate Geologists, Geoscientists, Petrophysicists, Reservoir Engineers and other petroleum industry personnel about capillary pressures and their use in the oil and gas industry. It provides best practice guidelines for capillary pressure measurement section and interpretation. Drainage and Imbibition saturation-height function derivation are detailed, as are their implementation in Petrophysical, Static and Dynamic Models. Some creative uses of these functions to greatly assist in reservoir understanding are also described,