I've just completed composing a scholarly book using LaTeX and it has been accepted for publication. Are there legal requirements for 1) acknowledgments or 2) permissions connected with the use of LaTeX in a published book? I don't see anything about the latter in the current versions of the docs for the packages I've used.
Edit: Frank Mittelbach has pointed me to a paper he has recently published on the history of the LaTeX Project Public License: TUGboat 32(2011)/1:83–94. Section 1.2 (p. 84) contains a digression on the
multicol license and its current status. He describes the
multicol "moral obligation" license as "perhaps the most curious license ever drawn up."