I'm reading this book called "Medieval Warfare: A History" and in the introduction, called "Warfare and the Middle Ages", the author, Michael Keen, states the following:

True, the military model of feudalism, which has been widely used in order to explain relations in the upper echelons of medieval society in terms of a hierarchic structure of contracts, based on grants of land by superior lords to lesser men in return for military service, is now looked at askance by many scholars.

English is my second language and I learned what "askance" means, which is already pretty good. I should probably just keep reading, but I'm annoyed that he didn't add a footnote to explain this point. This is basically what I've been taught in school so I'm curious as to why it's controversial.

edit: typo