This is a remarkably easy and inspiring book. If you work in a non-profit making organisation and have any responsibility for any one, or anything, else then you'll get something from this book.
It advises to see change as an opportunity. It reminds to put resources where results are and to place people where they can best perform. It carries sound psychology in suggesting that behaviour should be trained and not attitude and that nobody learns as much as a good teacher. It warns that nobody trusts you if you offer something for free.
It is not a book of aphorisms though - it is a book of well developed logical arguments supported by well examined examples. Any list of good management books will include the name Peter Drucker and this book demonstrates why.