The key books of masters level are full of mistakes.like the books of islamiat,arabic.political science.why?

i have gone through the key books of master level.like MA.ISLAMIAT,MA.POLITICAL SCIENCE,MA.ARABIC.the books contain grammatical mistakes,printing mistakes,the arabic verses and their wrong translation.why it is like so..no one is there to take notice of it?and the thing which make me sad is that what standard we can expect after reading these books.and i m sorry to say that all these key makers and their publishers are not sincere to us.