Re: Lithuanian Telephone Books #lithuania
Todd Brody asked about Lithuanian directories before 1930, writing that "The earliest directory on the Genealogy Indexer seems to be 1930." Genealogy Indexer actually includes many Lithuanian directories from before 1930, see:
However, many are Russian Empire-era "Commemorative Books" (e.g., for Kovno Gubernia, Памятная книжка Ковенской губернии) that are far from comprehensive. The most comprehensive are the Russian Empire Business Directories, Vsia Rosiia (1902, 1900, 1899, 1895, part of 1897, Вся Россия). (Note that due to the way those are printed and scanned, OCR accuracy is not super high, so some matches might be missed by searching.) Less comprehensive is the 1924 Baltic States + U.S.S.R. Business Directory (Rudl's Adressbuch der Baltischen Staaten und der U.d.S.S.R).
Todd mentioned a 1923 all-Lithuania telephone directory at the Library of Congress -- as far as I know, they have not digitized it and it is not otherwise online (on reputable websites).
near Washington, D.C.