Esperanto, the most widely-spoken constructed international auxiliary language, was the creation of Ludwik Lejzer Zamenhof, who first published it in 1887. Today Esperanto is estimated to have between 100,000 and 2,000,000 speakers worldwide. The most complete Esperanto dictionary is the 'Plena Ilustrita Vortaro', which is available both online and in printed format; but since the PIV is entirely in Esperanto, the need for a modern Esperanto-to-English dictionary remains keen for many Esperantists. Paul Denisowski's 'Esperanto-English Dictionary' can help fill a part of that need, on the basis of its sheer size alone, with more than 52,000 headwords. This extensive dictionary was compiled both from existing glossaries and from glossaries prepared by Denisowski himself, and it contains many words not usually found in smaller dictionaries, including an abundance of scientific terms, especially from the fields of medicine and mathematics. It is hoped that the publication of this dictionary will assist a new generation of Esperanto learners in their enjoyment of this unique language.