Fundamento de Esperanto is a 1905 book by L. L. Zamenhof, in which the author explains the basic grammar rules and vocabulary that constitute the basis of the constructed language Esperanto. On August
Foundation of Esperanto: Grammar, Exercises, Universal Dictionary . . .
Esperanto Day is a worldwide observance on 26 July, which celebrates the publication of Unua Libro, the first book in the Esperanto language, by the language's creator, L. L. Zamenhof on this day in 1
L. L. Zamenhof, Polish ophthalmologist and creator of Esperanto.