Do I need the permission of a corporation to publish an article or book about it?

Beginning Writer's Answer Book, edited by Jane Friedman

No, and if the company has been treated fairly, you should have no legal problems. However, if the company takes exceptions to any part of your work, you may have a lawsuit for libel on your hands. Even if what you write is true, the company might sue simply as a way of denying what you have written. Books about corporations written without their consent include Disney War and Under the Influence: The Unauthorized Story of the Anheuser-Busch Dynasty. Writers should exercise extreme caution when writing such material and make sure that all facts are verified.