In three volumes. This is an interpretative dictionary of the late ancient / mediaeval Greek language, covering the period from 146 BC (year of the Roman conquest) to the end of the first millennium (1000 AD). Each lemma contains a Greek word written in Greek and its interpretation in English.

E.A. Sophocles was a professor of ancient, Byzantine, and modern Greek in the Harvard University. As an author he is mostly known for the text-books he published for his students, among others the Greek Grammar and the History of the Greek Alphabet, and of course the famous Lexicon, the first edition of which was published as volume VII of the Memoirs of the American Academy under the title of "Glossary of Later and Byzantine Greek"΄the second edition was released in 1870 by the author himself under the present title and the third (postmortem) edition in 1887 by the President and Fellows of Harvard College; the current version is digitally corrected and reproduced from the second edition.
A note in the 1887 edition informs the reader that nearly two hundred evident inadvertencies were corrected; actually, minor corrections not changing the character of the whole work. In the current edition another, let's say, two hundred evident and not so evident inadvertencies were digitally corrected. For the most important of them, see the Hypomnema at the end of the third volume; except those, many other minor mistakes were silently corrected.