This edition constitutes a reprint of Niels Ege’s English translation of Rasmus Rask’s prize essay of 1818, which appeared as volume XXVI in the Travaux du Cercle Linguistique de Copenhague in 1993. The prize essay was published in Danish in 1818. In contrast to other works by Rask, notably his introduction to the study of Icelandic, it was never reissued until Louis Hjelmslev published a corrected version in Danish as part of his edition of Rask’s selected works. While Rask lived, a substantial part of the book was translated into German. The present work is, however, the only translation of the work into English and indeed into any other language. It is to be hoped that the field of the history of linguistics will hereby receive a new impetus to scrutinize the early beginnings of Indo-European scholarship. But, just as importantly, the translation of this work of genius reveals that even if details in the substantial treatment of the various branches of language have now been superseded, the theoretical parts of the book are still worth reading by all linguists for their own sake.