Permissions
When permissions are needed
You need to obtain permission to use such visual elements as diagrams from other books and screen shots of web sites. You ordinarily donโt need permission to use screen shots of the interfaces in applications. Most software companies offer a blanket permission to use them since it helps promote the use of their products.
You need to obtain permission to use text from other works when you are using significant portions of them. This does not mean you need permission to quote from another book. For quotes here and there all you need to do is cite the source. But if you are going to lift significant-sized passages, say 500 words or more or more than 20% of a shorter work, then you need to seek permission to use them. At that point you have probably exceeded the bounds of what is referred to as fair use. (See also: Plagiarism.)
Tips for obtaining the required permissions
Get started early! Donโt wait. It can sometimes take weeks or months for things to wind their way through legal departments. Contact your acquisitions editor or his or her assistant to get forms.
Providing proper attribution
Cite the sources of any material you quote or paraphrase. It is a good idea to cite any sources you consult. When using a diagram or table from a book or web site for which you have obtained permission, use a figure footnote or table footnote to credit the copyright holder and indicate that it is used with their permission. (See also: Plagiarism.)