Who is Power of Attorney

Power of Attorney is a document that allows a person to give or appoint another person in his or her place to manage all the affairs of his asset, which is usually a company during his/her absence. Suppose I am the head of a company and want to have a vacation for 20 days, then who is going to handle all the affairs of my company? There must be someone to look after them right? Thus I can give the Power of Attorney to someone so that he/she can look after them. It is a very important document since his/her decisions are going to affect the present and future of the company and thus must be drafted cautiously.