What 1905 paper introduced Einstein's special relativity?

The 1905 paper that introduced Einstein’s special relativity was “On the Electrodynamics of Moving Bodies.”

Einstein published the German original, “Zur Elektrodynamik bewegter Körper,” in Annalen der Physik on 26 September 1905. The paper began from two principles: the laws of physics are the same in all inertial frames, and light in vacuum has the same speed for all inertial observers. Together, those ideas overturned absolute time and required new rules for combining space and time.

The paper addressed a long-standing conflict between Maxwell’s electrodynamics and Newtonian mechanics. Earlier work by Hendrik Lorentz and Henri Poincaré had developed important mathematical tools, including the Lorentz transformations, but Einstein gave them a new physical interpretation that did not require a stationary luminiferous ether.

The title is sometimes confused with later works. “The Meaning of Relativity” is a much later book, while “Does the Inertia of a Body Depend Upon Its Energy Content?” was Einstein’s short follow-up paper containing the famous mass–energy relation. The 1905 relativity paper itself did not use the modern label “special relativity” as its title.