Problems in fluid mechanics are increasingly being solved using commercial computer programs. However, this approach requires a true understanding of the physics of the problem. The book contributes to a fundamental understanding of the relationships by clearly illustrating the physics of various flow forms. The basic mathematical equations, particularly the Navier-Stokes equations and the energy equation, are first presented in general form and explained in their mathematical significance. The physical/mathematical modeling of individual important flows or flow forms is then consistently derived from these fundamental equations. The authors systematically pursue the concept of deductive derivation. Dimensional analysis plays an important role.