There are many forms of plagiarism, some less flagarant than the examples I began with. However, you need to understand and avoid all forms of plagiarism. Presenting someone else's words or ideas as your own--in any form--constitutes plagiarism. Some forms of plagiarism are probably not obvious to you, so I want to spell them out in detail. I think much plagiarism is inadvertent and unknowing. I want to help you avoid that potential embarrassment.
Let's suppose you were assigned to write a book review of Theodore M. Porter's book, Trust in Numbers: The Pursuit of Objectivity in Science and Public Life (Princeton, NJ: Princeton University Press, 1995). In preparing to write your paper, you come across a book review by Lisa R. Staffen, published in Contemporary Sociology (March, 1996, Vol. 25, No., 2, pp. 154-156).
Staffen's review begins as follows: