With an emphasis on both theory and experiment, this text describes the behaviour of homogeneous and density-stratified fluids over and around topography. In examining the similarities between the flow of a river over a barrier or weir and the flow of the atmosphere over a mountain range, this book presents a comprehensive synthesis of this topic in terms suitable for scientists, engineers, teachers and students of fluid dynamics. With this book, Professor Baines makes a notable contribution to the fields of fluid mechanics and geophysical fluid dynamics. The text will be a great asset to graduate and advanced undergraduate students, as well as to research professionals.