Grid-based typesetting in LaTeX

The first edition of Rosalind Gibson's /Principles of Nutritional
Assessment/ was jointly typeset by her husband Ian and myself
in the years preceding its publication in 1990; the preparation
of this edition was the subject of one of my very first talks
at a TUG meeting.  Now, fifteen years later, Ian & I have again
collaborated in the typesetting of the second edition, which --
unlike the first -- is typeset in two columns on a strict grid.
LaTeX is not easily coerced into grid-based typesetting, so the
main thread of this talk will be the various measures we used to
achieve the desired effect.