Many of the important actors and decision makers in the armies of Spain, Portugal, the United Kingdom and the First French Empire are included.

[1] Oman's writing style is late Victorian, cleverly humorous, and genial in places, demonstrating a facility for story-telling.

[1] Regarding scholarship, Oman went "through everything available" and then dug for more, discovering diaries, memoirs, military dispatches, general orders, "parliamentary papers", filed newspapers, pertinent national archives, and so on.

[2] Oman also stated that another reason for creating his historical account was the very large amount of source material that had become available since the publication of Napier's work.

[2] Producing this seven-volume history spanned nearly thirty years [6] and it demonstrated Oman's unflagging "industry, perseverance, and volume of reading.