In 1960 she gained an interview with Louis Leakey, the famous anthropologist, who encouraged her to study the mountain gorillas of Central Africa at first hand.

Although the book does not delve into the subject in depth, Mowat speculates that an ex-worker may have been hired to kill her by larger corporate interests opposed to her crusade to preserve the gorillas.

According to Stefan Kanfer of Time Magazine, "Mowat is scrupulously fair: he shows his subject antagonizing co-workers as she lurches from tantrum to euphoria and back again, but he praises her meticulous observations of animal life and her unceasing struggles with poachers and politics as she fights to save the mountain gorillas from extinction ... Mowat finally makes some convincing accusations of government-sponsored assassins.

[4] A reviewer for Publishers Weekly describes the book as "a gripping story from beginning to gruesome end, filled with drama, intrigue and love affairs...

Frank Reiser writing in Library Journal says "This gripping, action-packed story is essential reading for all who understand the sacrifice of self for the preservation of other species.