The title is cheesy and it may not be as general as you’re looking for, but “The Girl’s Guide to Being a Boss (without being a bitch)” by Caitlin Friedman and Kimberly Yorio has good insights, was written recently, and is very readable (so you’ve got a shot at your interns getting through it without too many groans). It’s not aimed at theater, but it talks a lot about managing personalities in a work setting, which is a lot of what stage managing is about. Though it’s written with a by women, for women slant, I think men might learn a few things too by looking at management from a new perspective.