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. Zamenhof declared, "an international language, like a national one, is common property." Zamenhof signed the work as "Doktoro Esperanto" and the title Esperanto stuck as the name of the language which, in Esperanto, means "one who is hoping".
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"). At the first Esperanto World Congress at Boulogne in the same year, a declaration was issued, including the following:
The only basis of the Esperanto language binding on all Esperantists, which no one has the right to change, is the little work Foundation of Esperanto. If anyone deviates from the rules and models given in the said work, he can never justify himself with the words "thus desires or advises the author of Esperanto". Each Esperantist has the right to express any idea, which cannot be conveniently expressed by the material found in the Foundation of Esperanto, in such a manner as he finds most correct, as is done in every other language. However, for the unity of the language for all Esperantists it is recommended to imitate as much as possible the style that is found in the works of the creator of Esperanto, who has worked the most for and in Esperanto and knows best its spirit.
On the basis of Zamenhof's declaration that an international language is "common property", comparisons are sometimes drawn between Esperanto and what would today be called an open source project. However, the context of declaration of the language as being "common property" was that Zamenhof was abrogating his personal rights and privileges as its creator; the language itself remained subject to substantial controls on its modification.
• LibriVox free audiobook of Dr. Esperanto's International Language: Introduction and Complete Grammar (English translation of "Unua Libro" by R. H. Geoghegan, 1889), mp3 or ogg files, read by Nicholas James Bridgewater http://librivox.org/dr-esperantos-international-language-introduction-and-complete-grammar-by-ll-zamenhof/
These reprints of the Unua Libro have no ISBN.