Linguistic Aspects of Esperanto (in Esperanto: Lingvistikaj aspektoj de Esperanto) is a book originally written in the Esperanto language. It is based on a study by Professor John C. Wells published by Center for Research and Documentation on World Language Problems (In Esperanto: Centro de Esploro kaj Dokumentado pri la Monda Lingvo-Problemo) in 1978.
It is a scientific, descriptive analysis of Esperanto. The book is also available in German and Danish.[1]
Complete text of the original Esperanto book: http://www.pdf-archive.com/2012/02/07/lingvistikaj-aspektoj-de-esperanto-john-c-wells/