A monospaced version of ITC Garamond? I don’t think so.

There are monospaced versions of several ITC faces (including Avant Garde and Souvenir), so it wouldn't be completely implausible. I don't think they did ITC Garamond, though.

Not for the typewriter, it seems:
http://en.wikipedia.org/wiki/Selectric#Elements_and_fonts
But maybe for the Composer:
http://en.wikipedia.org/wiki/Selectric#Selectric_Composers

Yes, the Composer did have a Garamond typeface, but I don't believe it was ITC Garamond.

They had Press Roman, which was an imitation of Times, they had Aldine Roman, which belonged to the same general family as Bembo, and they had Bodoni and Garamond and Baskerville and, I think, Schoolbook. The only licensed font that they had was Univers, if I remember correctly.

As it happens, though, one of their monospaced fonts for the Selectric Typewriter, Adjutant (and its corresponding 12 pitch font, which is under another name), except for having round dots, was clearly designed to resemble... Goudy Old Style.

I was unable to find a list of composer fonts after a web search, but I remember another of its fonts: Pyramid. This font was an Egyptian, that is, it resembled Stymie.

Although its unit system was not as fine as that of Monotype equipment, I think the resolution of the system was probably satisfactory. Although the Selectric mechanism was a high-quality typewriter mechanism, though, typed characters would often be out of alignment, and that is usually the easiest way to distinguish texts composed in this way.

Instead of the resolution of the unit system, and in addition to the physical limit noted above, the most significant limitations of the Selectric Composer, in my opinion, were:

- It used one unit arrangement for all typefaces. Later electronic models allowed one to use a two-digit code to select different spacings, so as to use a Copperplate Gothic element with two sizes of capitals, or a Cyrillic element, but the first model was mechanical.

- In order to be able to handle type sizes up to 11 points on the existing Selectric typeball, the widest characters (capital M, W) were not as wide as they should have been relative to other characters in the same font. Instead of 9 units, they should have been 11 units, it seems, as can be seen by comparing the ratio between Monotype width and Selectric Composer width.

Oh, yes: I had a good laugh when in my Google searches I found that IBM had issued a system of font classification in which Times Roman was given as the canonical example of one class of type, and Press Roman, basically their copy of Times Roman for the Composer, was given as the example for a related, but distinct type classification.

There was also Theme, which resembled Optima.

On page 16 of this 18-page document you can find the showing of some proportional fonts for the IBM Selectric Composer. They came in several point sizes. I loved using Journal Roman; that was a simplified version of Janson (Kis). However, I do not recall any version of Garamond that was developed for the Composer.

I'm afraid you are right, and I was mistaken. I have a copy of a book that was clearly typeset on a Selectric Composer, "Modern Computer Concepts: The IBM 360 Series" by Edward J. Laurie (South-Western Publishing Company), and the font in which it was chiefly set looked to me like Garamond Bold - but it was actually Journal Roman.

Originally, the Composer had the following five fonts available for it: Press Roman, Univers, Aldine Roman, Bodoni Book, Pyramid. The others - Theme, Journal Roman, Classified News, Baskerville, and Copperplate Gothic - were added later.

I've just taken a look at a specimen of ITC Garamond, and in some searches, I noticed some comments here criticising ITC Garamond as not being a particularly good or authentic Garamond. It turns out that ITC Garamond, like Linotype Garamond Bold No. 3, closely resembles the font in the book I have that I think is actually Journal Roman.

So this ends up tying into the original poster's query. I do know that there are fonts which differ in appearance that are called Garamond - looking at fonts that came with a word processing program, and fonts that come in various collections of inexpensive fonts has led me to that.

Of course, I also know what Garamond should look like; Grillot de Givry's book about witchcraft and the like is one recent example of a book set in a... standard... version of the face.