Leipzig: Johann Ambrosius Barth, 1916. Wraps. First Edition. 64 pp. 8vo. Light brown paper wraps with mild spotting, lower right corner of cover and text block has a light stain through p. 7. Previous owner's signature in ink at upper right corner of title page. Quite clean overall. "Druck von Metzer & Wittig in Leipzig" on verso of title page as well as "Metzger & Wittig, Leipzig" on rear cover at base of ads that list publications only of 1916 and prior, unlike later printings. Very Good.
The first separate edition of Einstein's Theory of Relativity, which Einstein developed and revised between 1905 and 1915. Not an offprint of the article published in Annalen der Physik 49 which was often believed, but a separate publication with revisions and corrections and an added introduction by Einstein.