[5] In the prologue of the book, Holiday explains how finding early successes led him to the realization that ego can cloud ambition and hinder personal and professional growth, particularly when accomplishments are tied to self-worth.

[8] Ego Is the Enemy puts forth the argument that often our biggest problems are not caused by external factors such as other people or circumstances.

[5][11][12] Ego Is the Enemy provides both cautionary tales as well as positive anecdotes about ego, citing numerous historical and contemporary figures including Christopher McCandless, George Marshall, John DeLorean, Larry Page, Paul Graham, Steve Jobs and William Tecumseh Sherman.

[5][6][13][14] Ego Is the Enemy has received generally positive reviews, with Outside magazine commenting, "Holiday takes philosophy out of the ivory towers and translates often-dense concepts into actionable insights.

[18] The book went on to achieve bestseller status lists by USA Today, Chicago Tribune, and Publishers Weekly.