Electronic mail, often called "email," is a way to communicate with people as close as your office or as far away as the other side of the world. You type a message and put addresses on it; email programs use your computer and a network such as the Internet to deliver the message. Email programs run everywhere from microcomputers to supercomputers (of course, this book covers MH and related email programs, which run under UNIX). The people who read your messages don't have to use the same mail system as you do; their computers don't need to run UNIX.
Messages usually arrive anywhere from a few seconds to a few hours after they're sent. (They're held at computers along the way if a connection can't be made; also, some computers send mail in batches periodically.) The recipient can read your message, print it, send a reply to you and other people who were copied, file it, remove it... right away or whenever it's convenient.
Email is getting to be a part of life. It connects people on all kinds of computers, handles an uncountable number of messages every day, and lets you stay in contact when you're not in your office. Email provides a handy way to get information to and from busy people without playing telephone tag or interrupting them with a phone call. You can use email to announce or arrange meetings, discuss problems, share opinions among members of a group, and much more. Of course, email isn't the answer for everything. Sometimes a phone call or a FAX is easier and quicker.