This has been waiting for me to get to it for a while; now seemed a good time to dive into it. Having read a very large amount of history from a number of periods and countries, I'm not really surprised by what may be classed as "cruelty and atrocity" in medieval warfare - it happened, there's no doubt - and for whatever reasons. But it's interesting to see it incorporated as a theme into a historical non-fiction book. This book is particularly important due to the wide geographical and chronological scope in which the theme is explored. Having said that, the focus is on England, France and the Crusades - there is no in-depth exploration of the theme in the context of Italy or Sicily, Scandinavia, the Iberian states or other European areas.
To balance out the other side of the story i.e. why would knights who portray themselves as perfect examples of chivalry appear to commit such acts - I suggest reading around chivalry and its role in the middle ages - perhaps The Knight and Chivalry by Richard Barber would be a good start - and even some specific reading around histories of the Knights Templar, Knights Hospitaler and the Teutonic Knights. It's important to understand that while chivalry (and its concomitent rights and responsibilities, codes and literature) may have played little to no part in actual warfare, it was still, and for many valid reasons, a very important part of medieval culture, and remained relevant to large sections of society.
It's also important to realise that savagery, cruelty, atrocity, whatever you want to call it, was not absent from political or religious life outside warfare in medieval times (or any other time, for that matter). Being burnt to death for being a `heretic' or a `witch', being boiled to death for poisoning someone, or being hanged, drawn and quartered as a traitor - are these more or less `barbaric' fates than those dealt or suffered in medieval warfare? The entirety of medieval culture needs to be explored in order to be able to pass a balanced judgment on the `normality' or otherwise of the methods used in warfare.
These are not criticisms of the book; merely reminders that these things need to be studied not in isolation, but in conjunction with other aspects of medieval life in order to be able to go some way to understanding the `mentalité' of the people who lived in those times. A good read; recommended for anyone interested in Medieval European history.