Written with a reasonably dry (and sometimes dark) sense of humour, this book chronicles the conflicts on the South American continent during the 19th century, with brief forays into the 18th and 20th centuries, at the start and end of the book, respectively.
Compared with the much larger conflicts of the 20th century, these conflicts are small, and seem almost comical (although undoubtedly not to those involved in the actual shooting). The cause of these conflicts was invariably financial - either a European power (most likely Britain) attempting to redress a supposed wrong, or a conflict between two (or more) South American countries over resources - in which the Europeans (again, most likely Britain) would likely get involved. This was the era of "gunboat diplomacy" and the Europeans were rarely hesitant to use the threat of military intervention to obtain a favourable political or economic outcome.
As the title suggests, unless you are a very keen student of history, you may not be aware of most of these conflicts, and this book can fill in some gaps in your knowledge.