The most complete memoir or primary account in English of two of the most important phases of the Thirty Years' War, Monro's Expedition is a regimental history, a guide to would-be mercenary officers, a social history, and a window into an earlier era. Although the Thirty Years War (1618-1648) ended three and a half centuries ago, it continues to intrigue readers as one of the most devastating wars in modern European history. Initially a religious/political confrontation, the conflict soon expanded into a continent-wide series of wars. Monro's account of his experiences is one of the most important primary sources of the period.

From the creation of new tactical formations to improved military technology, the sheer magnitude of the crisis required new methods of waging war. Firsthand accounts by the combatants themselves are virtually non-existent, as rank and file soldiers were rarely literate, and their officers were only slightly more educated. Monro was a Scot who wrote proudly of his Scottish regiment and of his Scottish soldiers. Brockington's account retains the original spelling and punctuation and includes the original pagination within the new text for the benefit of readers searching for information cited elsewhere. Glossaries provide ready reference for place names, proper names, and archaic terms.