This article is from the Literate Programming FAQ, by David B. Thompson email@example.com with numerous contributions by others.
In contrast to Eric's and Norman's comments, I'd like to interject
from an anecdotal perspective.
I first ran across the idea of literate programming in 1992 while
poking around George Greenwade's TeX archive (at niord.shsu.edu) and
stumbling on some of the tools. My first experience was tinkering
with cnoweb, see Section ``cnoweb''. I used cnoweb to document a
simple Bernoulli equation toy I built (in C) while working on a one-
dimensional hydrodynamic model (in Fortran). I was convinced that
literate programming had promise (although cnoweb really qualifies as
a pretty-printing tool).
After reading Sewell's book, I kept hunting through the tools
available until I found things that worked for me. (More here as I
have time to develop the story.)