I originally started reading this book about twelve years ago and I stopped a little more than halfway through. I regret not being able to remember why I didn't finish it, though in retrospect I'm glad that I didn't, as starting it over has deepened my appreciation for what an amazing book this is.
The title is deceptive, though, as this book is much more than a study of merchants in the Middle Ages. What Peter Spufford has done is provide an accessible explanation of the nature and forms of commerce in medieval Europe. This may sound like a dull subject, but in Spufford's hands it is anything but. Demolishing many myths, he demonstrates that the medieval European economy was both highly integrated and increasingly sophisticated, with numerous business innovations (such as marine insurance and the holding company) pioneered during this era. In successive chapters he describes such aspects of the medieval economy as markets, commodities, and trading routes, explaining what was traded, where, and why. It's a fascinating take on an era more often associated with armored knights and peasants, any one that demonstrates that "globalization" is hardly a phenomenon exclusive to our modern era. Simply put, this is a magnificent study, and one that needs to be read by anyone interested in the Middle Ages.