The Alt-numpad entry works for input of ASCII values, and in the later Windows versions/Office for Unicode too, if you get sufficient of the "Internationalization" accessories, and if you're using a Unicode font. Of course, when you use a "strange" character, the reader has to have an installed font that is able to "draw" it. We've had quite a lot of discussion in some other threads about "why can't I see that character."

The tough part, for the editor, is looking at a strange character on screen or in print, and trying to figure out what the "author" intended it to be, so that you can get the correct character (i.e. the right ANSI number) in the font family that the book "designer" says you have to use. The problem with the "insert symbol" thing in Word is that you can't change what it inserts to another font, because it isn't a character.

I do have an accessory program that lets me highlight a few characters on screen, and will tell me what the ANSI numbers are for each of them. Unfortunately it only works for the low character (ANSI) set, and the really strange ones are often from the high Unicode character numbers.

Most publishers, especially book publishers, prefer to have a straight wordprocessor input from authors. By the time it goes through proofing, editing, possibly technical editing, layout, layout proof, page proofs, etc., there are plenty of opportunities for the "publisher" to convert, at the appropriate time, to whatever system is needed. A few journals, particularly those associated with academia, insist that the author must submit in TeX. A very few want word processor but with SGML tags. If you're going through a small publisher, or self-publishing, the requirements of the printer may dictate that you'll have to get stuff into Pagemaker or Framemaker, but usually that's the job of a layout person and the editing crew; and the less "layout" the author has done, the easier it is for them to get it right.

It is very important that you talk to your publisher about what his requirements are before you go too far with something.
We once helped a "friend(?)" with his 395 page book that the he had typed in text files, which was appropriate, but all in UPPER CASE "because he thought it would be easier for his reviewers to read." The problem is, he didn't call us until his publisher rejected it as "unsalvageable," so we got it two days before it was supposed to go to the printer. (And that was in the days of DOS Word 2.)

John