The Unua Libro (, First Book) was the first publication to describe the international language Esperanto (then called Lingvo Internacia, "international language"). It was first published in Russian on July 26, 1887 in Warsaw, by Dr. L.L. Zamenhof, the creator of Esperanto. Over the next few years editions were published in Russian, Hebrew, Polish, French, German, and English. This booklet included the Lord's Prayer, some Bible verses, a letter, poetry, the sixteen rules of grammar and 900 roots of vocabulary. In the book Zamenhof declared, "an international language, like a national one, is common property" and renounced all rights to the language, effectively putting it into the public domain. Zamenhof signed the work as "Doktoro Esperanto" (Doctor One-Who-Hopes). Those who learned the new language began to call it "Esperanto" after Zamenhof's pen name, and Esperanto soon became the official name of the language.
The first English edition, entitled "Dr Esperanto's International Tongue", was translated by Julian Steinhaus. When Richard H. Geoghegan pointed out that Steinhaus's translation was in very poor English throughout, Zamenhof destroyed his remaining copies and engaged Geoghegan to produce a fresh translation.
In 1905, Zamenhof re-published the sixteen rules of grammar, in combination with a "universal dictionary" and a collection of exercises, in a work entitled Fundamento de Esperanto ("Foundation of Esperanto").