The intervening seventeen chapters deal with the Civil War itself and cover, among other topics, Britons working in medical aid, foreign correspondents, the involvement of the Independent Labour Party, and the experience of those imprisoned in camps by Franco's Nationalists.

"[3] Alan Lloyd of the Morning Star praised Baxell's "pre-eminent knowledge of the British volunteers" and use of their own words to tell the stories; and wrote "The book is beautifully written and it's a totally absorbing read".

Mates identified Baxell's inclusion of a chapter on those who fought for the Nationalists and "the wealth of detail [he] provides of the individual experiences of British fighters" as strengths, and praised his collation of published and unpublished accounts, interviews, correspondence and archival sources.

[2] Mates also published a review in the academic journal Contemporary British History in which he also noted Baxell's attentiveness to the conflicts between the International Brigades and the anti-Stalinist POUM, who some Communists claimed were acting on behalf of the fascists.

Concluding, Mates noted "that Unlikely Warriors is tailored to appeal to a wider market than simply academics" and described the book as "a well researched, largely balanced, highly readable and accessible narrative".