I also recommended David Allen’s Getting Things Done, but Get Organized! is written to specifically address the needs of school administrators.
Buck writes from the perspective of a (presumably small-district) elementary principal, but his advice is applicable to anyone in school leadership.
Most productivity books offer variations on conventional wisdom, but I found many of Buck’s ideas interesting and original, such as how to keep reference material for current projects handy using your tickler file system. He also describes how to use Outlook’s Tasks feature in a way that’s accessible to non-power users. Even if you’re familiar with GTD, this one is worth a read.