Ludwig Prandtl, with his fundamental contributions to hydrodynamics, ae- dynamics, and gas dynamics, greatly in?uenced the development of ?uid - chanics as a whole, and it was his pioneering research in the ?rst half of the last century that founded modern ?uid mechanics. His book Fu]hrer durch die Str]omungslehre, which appeared in 1942, originated from previous pub- cations in 1913, Lehre von der Flu]ssigkeit und Gasbewegung, and 1931, Abriss der Str]omungslehre. The title Fu]hrer durch die Str]omungslehre, or Essentials of Fluid Mechanics, is an indication of Prandtl's intentions to guide...