Well productivity is one of primary concerns in field development and provides the basis for field development strategy. The primary focus of this book is to derive productivity formulae for oil wells in anisotropic reservoirs using straightforward mathematical techniques. Pressure transient analysis methods presented in this book are based on analytical solutions of the various forms of flow equation. It is the authors' opinion that the distinct advantage of the analytical methods is in their simplicity and the ability to identify correctly the main physical features of a given system. The analytical approach should be considered as an initial and necessary step by which the system is identified and first estimates of parameters are obtained. This book is arranged so that it can be used as an engineering mathematics textbook for graduate students in petroleum engineering, and can help the students have a complete understanding how mathematics can solve complex problems in reservoir engineering. This book is also a reference book for research scientists in petroleum industry and practicing reservoir engineers.