  Special relativity was discovered at the eve of the century, but finds its
roots in the 19th century efforts to understand the optics and electromagnetism
of moving bodies. These roots are reviewed in Parts 1 and 2, the latter being
specially devoted to the works of Lorentz and of Poincare up to 1904. Part 3
contains a detailed comparison of the works of Einstein and of Poincare in
1905. It is shown that both authors succeeded in constructing a coherent and
fully relativistic theory, although their ideas about the ether were radically
different. In Part 4, the question of the respective merits of the three
potential fathers of special relativity (i.e. Lorentz, Poincare, Einstein) is
discussed again, at the light of the preceding analysis and of the "post-1905"
developments of the theory.
