Since I spent the better part of two days puzzling over this
simple task I thought I would share. The American style for
running heads for non-fiction books is to have the current chapter on the
left (verso) page and the current section on the right (recto)
page. The text for each is near the spine and the page number near the
outside edge. The layout must be set doublesided in context. Two
commands are pertinent:

\setupheader[leftstyle=bold,rightstyle=bold]
\setupheadertexts[text][section][pagenumber][pagenumber][chapter]

On the actual page spread the chapter title wll be on the laft of
the spread and the section title on the right. But the
\setupheadertexts command has them reversed. The recto gets
described first and then the verso. The manual describes them
otherwise. left then right, but it is really right, then left.
Also the location parameter (first bracket pair) is mandatory for this
kind of header setup. And just putting [] won't work. You have to
specify a location.

Now old hands will have memorized all these peculiarities long
ago. I write this for beginners at the context game, like me.

--
John Culleton
Wexford Press
Free list of books for self-publishers:
http://wexfordpress.net/shortlist.html
PDF e-book: "Create Book Covers with Scribus"
available at http://www.booklocker.com/books/4055.html
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