In this paper I present a personal and scientific biographical sketch of Poincare,... He was so encyclopedic that he dealt with the outstanding questions in the different branches of physics and mathematics; he had altered whole fields of science such as non-Euclidean geometry, Arithmetic, celestial mechanics, thermodynamics and kinetic theory, optics, electrodynamics, Maxwell's theory, and other topics from the forefront of Fin de Siecle physical science. It is interesting to note that as opposed to the prosperity of biographies and secondary papers studying the life and scientific contributions of Albert Einstein, one finds much less biographies and secondary sources discussing Poincare's life and work. As opposed to Einstein, Poincare was not a cultural icon. Beginning in 1920 Einstein became a myth and a world famous figure.She makes several comparisons, including this:
In 1900 Poincaré was indeed in his highest ranks, and he was the most successful scientist in France and maybe in the whole world. However, Poincaré felt deep inside a very big crisis. The contents of his lectures, which he presented in the two international conferences (of physics and philosophy), and the talk presented in the Lorentz Festschrift celebrations, reveal this crisis pertaining to reconciling Lorentz's theory with the principle of relativity and the principle of reaction.QYes, they had different routes. Poincare's approach was to use the constant speed of light to synchronize clocks and define space and time; insist on the relativity principle as the best explanation of the Michelson-Morley experiment; invent a non-Euclidean geometry for four-dimensional spacetime using the Lorentz group and Minkowski metric; prove the covariance of Maxwell's equations for electromagnetism; and use symmetry invariance to find new laws of physics so that relativity becomes a spacetime theory that applies to everything.
It is interesting to note that Einstein had a crisis at about the same time. Einstein appeared to have been trying to solve the conflict between the principle of Galilean relativity and that of the constancy of the velocity of light in Maxwell's theory; and the conflict between the principle of Galilean relativity and Maxwell's theory and Faraday's law. Although both Einstein and Poincaré were feeling a crisis at about the same time, they followed completely different routes.
Einstein's approach was to make Lorentz's theorem of corresponding states into a postulate, and to use Poincare synchronization to give an exposition of Poincare's physical interpretation of Lorentz's local time. He is thus able to give a presentation of Lorentz's electron theory. Lorentz explained, "Einstein simply postulates what we have deduced".
Poincare's approach quickly became the backbone of special relativity. This is all explained in my book.