E-mails are convenient. They're quick and easy. They're used for all manner of communication these days. But some think the word "send" is the most dangerous four-letter word in the language.

We've all seen examples, recent and not-so-recent, of people getting in varying degrees of trouble over e-mails, from officials in the White House to an employee at a local school district who just quit his job in the midst of an investigation over "offensive" e-mails.

Robert Fulford, writing in the National Post (of Canada), offers his review of the new book, "Send: The Essential Guide to Email for Office and Home"(Knopf). It's by David Shipley, who runs The New York Times Op-Ed page, and Will Schwalbe, editor-in-chief of Hyperion Books. The book, Fulford says, has many examples and some good advice for those who use e-mail.

E-mail a friend about it. Carefully.