This encyclopedia is dedicated to the cities, towns, and castles of the multiethnic state known as the Grand Duchy of Lithuania, which now spans the territories of Belarus, Lithuania, Ukraine, Poland, Russia, and Latvia. The alphabetical section of the book attempts to describe all the notable settlements from this period, including cities, towns, and large villages that housed castles, as well as the castle complexes themselves—whether they still stand, lie in ruins, or have been completely lost to time, known only through chronicles and archaeological sources. The material covered in this encyclopedia spans from the 13th century to the end of the 18th century.