What is the difference between a writer and a copywriter?

Question:

What is the difference between a writer and a copywriter?

I think they deal with same task: writing, but once in a job advertisement I noticed that the company looked for both a writer and a copywriter, so it means they are diffrent.

Best Answer - Chosen by Asker: writer is the author of the piece. They do the research, write it, revise, edit.

A copywriter, writes the copy for the book. Copy is industry lingo for advertising. So a copywriter writes some blurbs, writes pitches to book stores, works with people in production on posters. They might also write press releases to be sent out to reviewers (the people that rate the books in magazines)