Table of contents : Introduction....Pages 1-17 Problem of uniqueness of minimal projections in Banach spaces....Pages 18-51 Minimal projections onto codimension one subspaces and a related mathematical programming problem....Pages 52-93 Kolmogorov’s type criteria for minimal projections....Pages 94-130 Isometries of Banach spaces and the problem of characterization of Hilbert spaces....Pages 131-152