Hi, sorry to resurrect an old topic, but I just got an advert from Oxford University Press that I thought might be of interest in re: this thread. OUP has what they call the "Word Lover's Set" of two books by David Wilton:
1. Word Origins and how we know them: Etymology for Everyone;
2. Word Myths: Debunking Linguistic Urban Legends.
They look rather fun to me (though not aimed at kids, but who knows? One of Harpo's favourite books is David Sacks's "Letter Perfect" about the history of the alphabet), and right now they're 80% off, according to my flyer!
www.oup.com/us/holidaysalepeace
minnie