In addition to the above answer, I might just add that in Orientalism, Edward Said established a binary between Orient and Occident. It was this binary that created the "Other" and that allowed the colonizers to form a cohesive Us identity in the corollary Us/Them binary. Postcolonialist professors embrace this criticism because of adherence to the precept that dignity derives from recognizing each group as equal as opposed to a Them inferior to or subservient to an Us.
The relevance of Said's binary of Orientalism to literature is that he contends (critics suggest boldly contends) that there could be no European literature from the end of the 18th century onward (at which time morality ceased being an individual choice of a code of conduct and became a cultural construct) as we know it because from Austen to Conrad, the Us/Them Orientalism binary is present. In works such as Austen's, it is present in a stark silence; in work such as Conrad's it is present with a passive Them as ineffectual background to the Us who have the agency, authority and rational capability to act.
The suggested length of an answer on this site is 90 words, so I can hardly do justice to this question, but I hope to give you some ideas.
To Said, orientalism is the idea that Western scholars have created an image of the Orient that is meant to fulfill their own preconceptions rather than to accurately depict what the "East" is like. This image of the Orient is usually quite negative -- the people are seen as weak and effeminate but strangely dangerous even so. Above all, the people are seen as fundamentall "other."
I would mainly critique this theory by pointing out that Western ideologies are fundamentally open. The West has a history of accepting ideas that come from outside itself. Please follow the second link for further critiques.
Orientalism is a political vision to the truth. The Arabian region is the only Eastern foretime that Europe has lived through. The aim of orientalism was to put the East and its foretime under the control of the West and to put its future planning to produce a new history for the world. Oriental writings expressed a strong fear of Islam and Arabs who represented the first military force. The positive side of orientalism is the appearance pf some Arab thinkers like Taha Hussain and Al-Tahtawi who studied the Arab history and tried to reply to the we sterns accusations and to correct the wrong ideas about Arabs.
What books of Taha Hussein and other Arabs thinkers deal with this issue?