It’s fine to reference or refer to other people’s work, but you often need permission to quote them.
Permissions is a grant of rights for the use of other’s copyrighted material to be used in your book. Examples of material that usually require permission to reproduce are a short quotation used to open a chapter, a line from a poem, song lyrics, pictures or images.
It is the author’s responsibility to clear these permissions from the copyright holder, which may be the artist, writer, photographer, their publisher, agent or estate. It’s important to remember that the author themselves may not have the legal right to grant you permission to reproduce their work.
Clearing permission can be a costly and time-consuming process, especially if you are quoting a famous work, or if you have a large amount of permissions. We recommend carefully considering whether the copyright material is vital to your work before submitting, or if you could remove or paraphrase it.
You do not need to seek permission if what you’re quoting is in the public domain, although it can sometimes be difficult to figure out whether it is or not. Contrary to popular opinion, there are no legal guidelines for the fair use of copyright material (under a certain number of words or percentage of the work), so tread carefully.