Still having a major headache trying to get the "titles=" field to behave as I expect (i.e. to restrict the values returned to those that match the title value).
If I configure this query:

http://en.wikibooks.org/w/api.php?action=query&list=allpages&format=xml&apprefix=The%20Devonshire%20Manuscript&aplimit=max&titles=The%20Devonshire%20Manuscript

I get a list of all the pages whose titles begin "The Devonshire Manuscript".

I'll then have to run each of those pages through a query like this to get the revisions for it:

action=query
prop=revisions
titles=[title field from item i of list generated above]
aplimit=max

The docs say that if I provide more than one title (using a pipe-delimited string), it will return only the most recent revision for each page in the list. What I want are all the changes made between time X and time Y on each of the pages, and this two-step process is the only thing I've figured out so far.

I suspect that I will want information sorted by users and not by pages, so I'll look into that next.