These first appeared in the late 19th century in Germany and flourished in the 1920s and 30s, when they were regarded as the future of typography. It's more a geometric design than the humanist design of Gill Sans, but less geometric than Avant Garde and Futura. To my mind it lacks elegance, and Adrian Frutiger's Univers shows how this kind of typeface should be done. Helvetica is one of the few fonts that is improved by its BOLD version. They're also very suitable for display work.
Courier is a typeface derived from typewriter styles.
A good one is OCR-B, designed by Frutiger. Note that monospaced fonts are less economical on space than proportional fonts. The following summary of their discussion may serve to clarify some of the more subtle points. Ideologically, yes, but not chronologically. I believe, for example, that Bodoni predates New Century Schoolbook or some such typeface .