This book provides a detailed account of a year-long expedition undertaken by Captain Wellby from September 1898 to 1899. The journey took him from Zeila on the Somali coast through "unknown Abyssinia" and on to Cairo. Wellby describes his experiences in the "devil-infested country of Walamo" and his dangerous trek to Lake Rudolf.

The narrative offers a "brief and simple description" of the country and people Wellby encountered, including his interactions with H.I.M. King Menelik II. He emphasizes the virtues and "redeeming points" of the Abyssinian character, differing from many contemporary writers who held a more negative view. The book includes detailed maps based on the surveys done by Wellby.

Wellby highlights the extreme hardships of the journey, including an incident near Lake Rudolf where he suffered from blood poisoning after cutting his finger on a tin, yet continued to march in agony to keep his followers' morale up. His journey from Addis Ababa to the Nile is regarded as "one of the finest in African exploration."