What is the author's style in Cry of the Kalahari by Mark James Owens?

The book is written in first person with Mark as the main voice. However, in the prologue, he makes the point that the entire book, though written in his first person, is truly a collaboration between he and his wife, Delia, who shares every moment of the Kalahari experience. Some chapters are marked "Delia" so in those cases, she takes the dominant role in relating the story of the chapter.

The ten chapters that are written by Delia are also written in first person.