The one minute manager is about describing the things the perfect manager does.
It tells mainly about 3 things that he "effective manager" does.
The first is the "One minute Goal Setting". This is about writing down 1-pg decription of the details of the task to be done and clarify and have a good understanding of the same with the subordinate.
This certainly does not take much of a time - so something around 1-min. Subordinate now knows what exactly has to be done.
The second is the "One minute praisings". Here the effective leader/manager (think about differences between a manager and a leader) catches the subordinate when he does the right things towards the goal. He then praises the subordinate for the same and builds confidence. Subordinate now knows that he is on right track and is doing right.
The third is the "One minute reprimand". Here the "effective manager" scolds and does something like contructive criticism if he comes to know about the wrong things the subordinate should not do. And later consoles him and clarifies the wrong path. Subordinate comes to know what wrongs he should not do.
Author has given excellent example of a bowling game in describing why these things really work.
In doing so every subordinate is becoming 1-min-mgr slowly. Sets goal, praises and reprimands and moves ahead. Easy to read how simple things that would also avoid Bureaucracy and introduce more tranperancy at work place.