Dr. Esperanto's International Language (), commonly referred to as ' (First Book), is an 1887 book by L. L. Zamenhof, in which he first introduced and described the constructed language Esperanto. First published in Russian on , the publication of Unua Libro marks the formal beginning of the Esperanto movement.
History
thumb|The original [[Russian language|Russian publication of Unua Libro and the 1887 Polish, French, and German translations]]
After many years of developing the language, Zamenhof completed Unua Libro by the spring of 1885 and spent the next two years looking for a publisher. In 1887, shortly after he married his wife Klara, his new father-in-law Aleksandr Silbernik advised him to use money from Klara's dowry to find a publisher. Following his advice, Zamenhof found a publisher in Warsaw, Chaim Kelter. On , Kelter published the book in Russian as International Language (). However, when Richard Geoghegan pointed out that Steinhaus's translation was very poor, Zamenhof destroyed his remaining copies and requested that Geoghegan produce a fresh translation.
Unua Libro was also translated into Hebrew, Yiddish, Swedish, and Lithuanian in 1889 and then into Danish, Bulgarian, Italian, Spanish, and Czech in 1890.
In part III, he presents an idea called the "universal vote", which is a campaign to allot 10 million signatures of people making the following pledge: "I, the undersigned, promise to learn the international language, proposed by Dr. Esperanto, if it shall be shown that ten million similar promises have been publicly given." He argues that this will prevent anyone from wasting time on learning the language since, once 10 million signatures have been gathered, there will be a significant population obliged to learn the language, rendering the language useful. He also welcomes critical feedback for the next year and promises to consider criticism before publishing a special booklet that will give definitive form to the language the following year (which was to be Aldono al la Dua Libro). Additionally, he lays out guidelines for a language academy to guide the evolution of the language in the future (which was to be the Akademio de Esperanto).
In the grammar section, he explains the Esperanto alphabet and sixteen grammar rules.
In the dictionary section, he presents a dictionary with 917 roots of vocabulary. In the hundreds of letters he received, he saw enough support to prompt him to publish Dua Libro in January 1888 and La Esperantisto in 1889, in order to provide more Esperanto reading material for those with interest. In 1889, he also published Russian–Esperanto and German–Esperanto dictionaries to increase Esperanto vocabulary, as well as Aldono al la Dua Libro, a supplement to Dua Libro, to establish the definitive form of the language, a document he promised in part III of Unua Libro.
By all measures, Zamenhof's "universal vote" campaign failed. By 1889, he had only reached 1000 signatures, a mere 0.01% of his goal of 10 million. Nevertheless, the Esperanto movement continued onward. Among the early supporters were educated Russian and Polish Jews, Leo Tolstoy and his followers, Eastern European freemasons, and speakers of Volapük who had lost hope in their language.