Classic texts in the field of analysis of flow in blood vessels have been written over the years and what these say is still valid today. However, our knowledge of pathophysiological mechanisms has changed with increasing rapidity over the past 20 years, as has our ability to visualize the three­ dimensional geometry of blood flow and blood flow velocity distribution within the in vivo blood vessels. Consequently, with the increased need to fully exploit the new imaging capabilities and our additional biological knowledge, this book is a welcome addition to our armamentarium used to achieve those new goals. the past pulsatile flow (and consequent wave reflections) was Whereas in often seen as "frosting on the cake" of analysis of blood flow problems or perhaps as an issue that should be understood only in a general sense, our new capabilities and understanding require more accurate analyses of spe­ cific systems, not just of constructs based on statistical data describing a vascular tree. Examples of this new need include the situation where the detailed branching geometry of an arterial tree is known from imaging and it is desired to see to what extent local fluid dynamic characteristics can explain the specific localization of disease such as atherosclerosis, or of the extent to which the heterogeneity of perfusion throughout an organ can be attributed to the vascular tree branching geometry or to the mechani­ cal properties of the vascular walls.