Well test interpretation, which is the process of obtaining information about a reservoir by analyzing the pressure transient response caused by a change in production rate, plays a very important part in making overall reservoir-management decisions. From the authors of Pressure Transient Testing and Well Testing, Spivey and Lee introduce the readers of Applied Well Test Interpretation to the fundamentals of this critical piece of decision-making by focusing on the most basic well testing scenario; a single-well test on a well producing a single-phase fluid, from a single-layer, homogeneous reservoir.