This new edition textbook is a comprehensive guide to hydrodynamics and fluid dynamics, addressing phenomena encountered in everyday life and critical engineering applications across multiple disciplines. Introducing brand new photographs and figures, an additional chapter, along with expanded appendices and a comprehensive subject index, this is an exposition on the application of the fundamental principles of mechanics and thermodynamics to understand fluid flow motion, forces, and energies. The book is divided into two major sections: ideal fluid flow and real fluid flow. Ideal fluid flow examines two and three-dimensional fluid motions unaffected by boundary friction effects, while real fluid flow addresses regions influenced by boundary friction and turbulent shear. Practical examples range from flow motion in kitchen sinks and exhaust fans to air conditioning systems. Engineering applications encompass fluid transport in pipes and canals, energy generation, environmental processes, and transportation systems including cars, ships, and aircraft. Additional topics include environmental wind flow, flow motion in pipelines and wate distribution in cities. The material illustrates how air flow around a vehicle body induces drag force that increases with the square of speed, contributing to fuel consumption. The lecture material is designed as an intermediate course for senior undergraduate and postgraduate students in Civil, Environmental, Hydraulic, and Mechanical Engineering.