Release date is 2026-02-03

Jana Srna and the Online Distributed Proofreading Team at https://www.pgdp.net

"Über die spezielle und die allgemeine Relativitätstheorie" by Albert Einstein is a popular scientific treatise written in the early 20th century. It presents an accessible, concept-first account of relativity, showing how our notions of space, time, motion, and measurement must be rethought, with minimal mathematics and a focus on physical meaning.

The opening of the treatise sets the aim and audience, then builds special relativity step by step: it distinguishes pure geometry from its physical interpretation with rigid bodies, introduces coordinates and reference frames, and defines inertial (Galilean) systems. It formulates the relativity principle, exposes the conflict with a naive addition of velocities and the constancy of light speed, and resolves it by operationally defining time and simultaneity via light signals, revealing the relativity of simultaneity and distance. From there it presents the Lorentz transformation, length contraction, time dilation, and the relativistic velocity-addition law, supported by experiments such as Fizeau, stellar aberration, Doppler shifts, and the Michelson–Morley result (without invoking ether). It highlights Lorentz covariance as a heuristic guide, revises mechanics at high speeds, and unifies energy and mass (E/c²), with c as a limiting speed. It concludes this opening portion by introducing Minkowski’s four-dimensional spacetime and then begins the transition to the general relativity principle. (This is an automatically generated summary.)

Originally published: Braunschweig: Friedr. Vieweg & Sohn, 1917