Is it acceptable for professors to plagiarise material for an academic textbook? I know a professor who has recently written two books which are used as textbooks/academic books. However, I spotted a pretty recurrent pattern of plagiarism. They copy sentences and sometimes paragraphs up to several hundred words from Wikipedia, other articles, books, reports without referring to that work through both of the books. Often when they do copy, they include the references they copy (e.g. they copy A which refers to B and C), and they keep the references to A and B. 

Is this in any way considered common practice? I obviously think not, but I am interested to ask whether I am simply too draconian in this regard.
Replicating large portions of material from other books without permission; copying major portions of published work without citation -- this is blatantly plagiarism at all angles. This is downright unacceptable unethical practice.