Running heads are there to help signpost where you are in the book: so they will carry a page number, maybe a chapter or part title, perhaps a section within a chapter, or in the case of a book by multiple hands, the author’s name.  In an ideal world the recto running head will include a description of what it is that’s being described on the opening you are looking at, making it almost like a running index.  Few are the books which have this sort of running head nowadays.

Designers get bored with designing the same book day in and day out, so they seek to mix things up, and occasionally come up with the bright idea of putting the running heads at the bottom of the page, where they rejoice in the name running feet.  This ploy is almost always a mistake.  A case might be made for running feet in the case of a double column book with lots of different elements, where they might provide a sort of calming base for a chaotic page.  But generally their pitter patter is just an annoying distraction.

The ultimate in idiocy (well idiocy in the running foot department anyway) comes when the designer omits the running foot on a chapter opening page.  Why would they do this?  Why, because you “never” have a running head on a chapter opening page, where it would get in the way of your beautiful chapter number and title layout.  (We seem to have forgotten that old convention of a drop folio in such instances.)  But if you have running feet you will certainly not have a running head on the chapter opener.  As the chapter opening pages are all listed in the contents list they are among the few pages which you are most likely to look up, and this makes taking off the page number from some mistaken sense of convention is really dumb. A running foot on a chapter opener will look no worse than it does on any other page, and will carry the benefit of providing the page number too.  Admittedly if your running foot is carrying chapter title this may lead to a certain redundancy of information, but that’s less annoying than the perverse omission of a repeating element in the design for absolutely no good aesthetic or logical reason.

Even less tolerable is the designerly quirk of putting the running head in the outer margin, reading perpendicular to the text.  Stanley Morison, father of good type design, and of Times Roman, always argued that the reader should never be aware of presence of the designer: making him turn the page at regular intervals is a great way for the designer to demand attention.