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 the reader on a carefully
thought-out path through the di?erent areas of ?uid mech- ics. On his
way, the author advances intuitively to the core of the physical
problem, without extensive mathematical derivations. The description of
the fundamental physical phenomena and concepts of ?uid mechanics that
are needed to derive the simpli?ed models has priority over a formal
treatment of the methods. This is in keeping with the spirit of
Prandtl's research work. The ?rst edition of Prandtl's Fu]hrer durch
die Str]omungslehre was the only book on ?uid mechanics of its time
and, even today, counts as one of the most important books in this area.
After Prandtl's death, his students Klaus Oswatitsch and Karl Wieghardt
undertook to continue his work, and to add new ?ndings in ?uid mechanics
in the same clear manner of presentation.