I’m glad for anyone to reprint anything. However, the publication that commissioned and paid for the essay in the first place asks that you note where the essay originally appeared (this is bracketed at the top of each essay). Many periodicals also request that you wait at least 90 days from when the item was first printed. Apart from those restrictions, it is usually all right to reprint a piece that originally appeared in a publication. However, if it is an excerpt from a book, the publisher has stricter reprint rules. Not sure? Contact me.