This volume offers a reconstruction of the Proto-Ainu language based on the comparative method and internal reconstruction. It is divided into three parts: the first is dedicated to the reconstruction of Proto-Ainu phonology (vocalism, consonantism and prosody), the second represents a vocabulary of reconstructed Proto-Ainu lexical items and the third deals with the problem of the genetic affiliation of the Ainu language. In this study, this problem has been approached from the point of view of systematic comparisons of reconstructions, not the straight comparisons of the forms attested exclusively in modern langages, which was the major set back of the previous scholarship on genetic affiliation of the Ainu language. The volume also includes the 19th-century vocabulary of the Kuril Ainu by I. Voznesenskii.