"'Ivar the Viking' is to be thoroughly recommended. The story is characteristically spirited, and the romantic part leaves nothing to be desired."
Chicago Tribune.
"It is full of vigor, and seems to bear internal evidence of truthfulness as regards its historic side. Ivar was a Viking whose adventures the juvenile reader, and particularly the boy juvenile, will follow with eager interest."
Philadelphia Press.
"Of the subsequent adventures of Ivar and his foster-brothers the interested reader must gain knowledge in the pages of the delightful narrative itself. Suffice it to say that there is no lack of romantic incident at any stage of the story. The prowess of the four Vikings is always potent; they fall in love; Ivar fights a duel, and then wins the loveliest of brides. There is throughout the volume the stimulating air which blows through the Sagas, the nipping salt air of the sea."
Richard Henry Stoddard.
"There is that in Mr. Paul Du Chaillu's 'Ivar the Viking' which not only satisfies the lover of romantic adventure, but carries the scholar back into the remotest period of Scandinavian history. Beyond all living writers this traveller in and explorer of many countries has collected the documents and discovered the secrets of the Norselands."
New York Times.
"The reader who has begun with a blank mind closes the volume with a tolerably clear impression of a very energetic, powerful, and wealthy young Viking, capable of strong affections and disaffections, foremost in games and fights requiring physical force, and with a vast number of habits and customs. It is a history that interests through its simplicity."
Boston Transcript.