For graduate students and researchers interested in differential geometry and theoretical physics, Falcitelli, Anna Maria Pastore (both U. of Bari, Italy) and Steve Ianus (U. of Bucharest, Romania) provide a systematic exposition of the basic tools on the theory of Riemannian submersions and its developments. Submersions are special tools in differential geometry, but also play a role in Riemannian geometry, especially when the manifolds involved carry an additional structure. They are in a sense a counterpart of immersions, but the corresponding theories and histories are quite different.