For PSEO World History I have to write an essay on this book, the essay is asking to assess how objective Manchester is, see if there is any bias.
I know this book is inaccurate and I am very much a layman. It was hard to read through. Are there any academic sources that have thoroughly ripped it apart? Any academic works that try to dispel these misconceptions about the middle ages would work nicely too.
I already have seen and cited the Speculum review of it.
Because this question is relating to an essay (though it's very much allowed, don't worry!), I would just take the time to remind all potential contributors that whilst our rules DO permit people to ask for help with their homework and for users to help them, answers (and further questions) should remain focused on clarification or resources. This policy is further explained in this META Thread.
Additionally, while our users may be able to help you out here, we hope that you also will take the time to check out our six-part series, "Finding and Understanding Sources", where several of the community's expert contributors have written guidance on how to conduct historical research, much of which applies to writing papers for higher education.