This popular book has been thoroughly updated for its fourth edition, and is even more directed towards the leadership demands on managers, both within the school and in its community setting.
Good book, some chapters were extremely useful, others not so much for me. If you run a school all chapter will certainly come in handy, specially for managers. But if you somehow manage language related things, there are a few chapters that will be enormous help, and others you can skip. This is definitely more focused on management problems and not so much in teaching, so the knowledge can be extrapolated to other things.
EDIT: It's my second round with this book. I read it a while ago when I had an office job and was in charge of language trainning for employees. Back then it helped very little, but now that I'm working at college as part of the Translation department it felt like a different book. There is many things that made a lot more sense now and that I can actually put into practice. Definitely useful for school environments.