During its first 100 years, Riemannian geometry enjoyed steady, but
undistinguished growth as a field of mathematics. In the last 50 years
of the 20th century, however, it exploded with activity. This volume
marks the start of this period with Rauch's pioneering paper of 1951,
which contains the first real pinching theorem and a leap in the depth
of the connection between geometry and topology. Berger then provides a
survey of the main developments in Riemannian geometry in the final 25
years of the 20th century.