We mourn the passing of Claude Piron on January 22nd, the famous Esperanto writer and intellectual. The Wikipedia article on Piron has the following exerpt on his works:
His most famous works are Gerda malaperis! and La Bona Lingvo (The Good Language). Gerda malaperis! is a novella which uses basic grammar and vocabulary in the first chapter and builds up to expert Esperanto by the end, including word lists so beginners can easily follow along. In La Bona Lingvo, Piron captures the basic linguistic and social aspects of Esperanto. He argues strongly for imaginative use of the basic Esperanto morpheme inventory and word formation techniques, and against unnecessary importation of neologisms from European languages. He also presents the idea that once one has learned enough vocabulary to express oneself, it is easier to think clearly in Esperanto than in many other languages.
The book (available online) has recently been made into a movie.