Nance offers a four-point plan to defeat ISIS, including airpower and special forces, Internet tactics, strengthening the Syrian military, and engaging Arab world states.

Nance grounds the reader within the context of Islamic history, including the Battle of Nahrawan, controversy regarding Shia–Sunni relations, evolution of the Qarmatians, and the Mahdist War.

Nance writes that these strategies lead to gross violations of human rights, including sexual assault and child soldiers.

Nance writes that ISIS usually engages in the military tactics of mountain warfare and frontal assault, later encouraging each other through social media discussing their combat operations.

[1][2][3] Defeating ISIS concludes with a strategy proposed by the author to weaken the organization both their combat operations and their ability to garner new followers.

[18] Prior to his work on Defeating ISIS, Nance had already extensively researched the topic, while writing a treatise specifically geared for the intelligence community to educate them in textbook format on the growth over time of Al-Qaeda in Iraq.

[19] Defeating ISIS was contracted for publication with Skyhorse Publishing in November 2015, originally slated for a January 2017 release date.

[25] Defeating ISIS made The New York Times Best Seller list at number nine for the week of July 3, 2016, in the section for "E-Book Nonfiction".

[1] He praised the author's ability to structure the book as a reference resource, writing, "there is a wealth of factual information on ISIS".

[1] Moon concluded, "This book is a good reference source for anyone in the professional field and for individuals seeking to understand the enemy and what we and our allies face.

[31] The Guardian national security reporter Spencer Ackerman praised the author's expertise, citing the caliber of his works The Terrorists of Iraq and Defeating ISIS.