The book 's title is a reference to the means by which farm - based societies conquered populations of other areas and maintained dominance, despite sometimes being vastly outnumbered -- superior weapons provided immediate military superiority (guns); Eurasian diseases weakened and reduced local populations, who had no immunity, making it easier to maintain control over them (germs); and durable means of transport (steel) enabled imperialism.
what is steel in guns germs and steel
durable means of transport